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<?xml version="1.0" encoding="UTF-8"?><rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom" version="2.0"><channel><title><![CDATA[Reativa Tecnologia]]></title><description><![CDATA[Transformamos programadores iniciantes nos melhores programadores do mercado.]]></description><link>https://blog.reativa.dev</link><generator>GatsbyJS</generator><lastBuildDate>Sat, 27 Feb 2021 08:35:19 GMT</lastBuildDate><item><title><![CDATA[Mentoria para programadores iniciantes]]></title><description><![CDATA[Olá, eu me chamo Paulo Luan. Sou programador há 10 anos, tenista de mesa amador e apaixonado por disrupção. Fui parte de projetos como o…]]></description><link>https://blog.reativa.dev/mentoria-pauloluan/</link><guid isPermaLink="false">https://blog.reativa.dev/mentoria-pauloluan/</guid><pubDate>Fri, 08 Jan 2021 00:00:00 GMT</pubDate><content:encoded>&lt;h2&gt;Olá, eu me chamo Paulo Luan.&lt;/h2&gt;
&lt;p&gt;Sou programador há 10 anos, tenista de mesa amador e apaixonado por disrupção. Fui parte de projetos como o desenvolvimento do Internet Banking do maior banco da América Latina e diversos e-commerces das maiores varejistas mundiais como Motorola e Embraer. Centenas de milhões de reais já passaram através dos códigos que desenvolvi, além de ter contribuído com o desenvolvimento do sistema que &lt;a href=&quot;https://bit.ly/38UQA3Q&quot;&gt;irritou o presidente do Brasil em 2019&lt;/a&gt; 😂&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://media-exp1.licdn.com/dms/image/C4E12AQGAoCZCBrGP6w/article-inline_image-shrink_1000_1488/0/1605780554533?e=1615420800&amp;#x26;v=beta&amp;#x26;t=LQPux0ShUPX2ZVHPz08VFS-OGhCl91F3N74rRILhYQ8&quot; alt=&quot;No alt text provided for this image&quot;&gt;&lt;/p&gt;
&lt;p&gt;já mentorei mais de 2.547 programadores: no &lt;a href=&quot;http://bit.ly/pauloluan-insta&quot;&gt;Instagram&lt;/a&gt;, nas consultorias e na vida.&lt;/p&gt;
&lt;p&gt;Hoje, estou iniciando uma nova etapa e colocando em prática tudo que aprendi:&lt;/p&gt;
&lt;h2&gt;Ensinando todas as coisas que eu considero ter inestimável importância para ser um bom dev, para que você possa chegar muito mais longe do que eu, no menor tempo o possível.&lt;/h2&gt;
&lt;p&gt;Antes de começarmos, vou deixar uma coisa bem clara: SIM eu tenho fins lucrativos, mas não sou uma daquelas páginas que te prometem dinheiro fácil.&lt;/p&gt;
&lt;p&gt;Eu não vou fazer aqueles vídeos bizarros falando que “você vai enriquecer em apenas 7 dias no conforto do seu lar”. Estou te apresentando uma oportunidade para você se tornar um programador de alto nível, você pode aproveitá-la ou não.&lt;/p&gt;
&lt;p&gt;Porque diabos eu começaria o texto assim, dizendo que não te prometo dinheiro fácil? Porque tenho um compromisso sério com a verdade e com a honestidade. Odeio quem tenta levar tudo na conversa, enrolando com um monte de baboseira e discursos falsos para te vender produtos de merda por 5 mil reais.&lt;/p&gt;
&lt;h2&gt;Minha pegada é ir direto ao ponto. Assim economizo o meu tempo e o seu.&lt;/h2&gt;
&lt;p&gt;Se você chegou até aqui é porque me conhece, e já viu pelo menos um pouco do meu trabalho. Sei disso porque não me interesso em enviar spam para desinteressados, já que essa não é minha filosofia de trabalho.&lt;/p&gt;
&lt;p&gt;Como já mencionado, nos últimos anos, estruturei a engenharia por trás de diversos projetos de software, que foram usadas por milhões de pessoas ao redor do mundo.&lt;/p&gt;
&lt;p&gt;Mas eu não fiz estas coisas sozinho, eu sempre contei com equipes fantásticas e pessoas talentosíssimas, e Isso me ajudou a entender como o mercado funciona, o que dá certo e principalmente: O que não dá.&lt;/p&gt;
&lt;p&gt;“Então onde você quer chegar?”, você deve estar se perguntando.&lt;/p&gt;
&lt;p&gt;Quero dizer que sou competente, e sei exatamente daquilo que estou falando. Nada que eu disser nessa página, ou colocar em meus cursos, não foi feito por mim antes. Todas as teses, ideias e propostas foram testadas pelo menos uma vez, com meu próprio tempo e dedicação nos diversos lugares que passei durante a última década desenvolvendo código.&lt;/p&gt;
&lt;p&gt;Ou seja:&lt;/p&gt;
&lt;h2&gt;EU SEMPRE MANTENHO MINHA PELE EM RISCO.&lt;/h2&gt;
&lt;p&gt;Agora eu te pergunto:&lt;/p&gt;
&lt;h2&gt;“O que é que os maiores programadores do mundo têm em comum?”&lt;/h2&gt;
&lt;p&gt;Eles resolvem problemas, são pragmáticos e autodidatas.&lt;/p&gt;
&lt;p&gt;A essa altura você deve estar se perguntando: “O que isso tem a ver comigo e com a minha realidade?”&lt;/p&gt;
&lt;h2&gt;TUDO. Qualquer pessoa pode se tornar programador, os princípios são os mesmos.&lt;/h2&gt;
&lt;p&gt;Não aprendemos direito na faculdade o que é possível fazer com todo esse conhecimento. A faculdade peca em muitos aspectos, e você já deve ter reparado que tenho opiniões bastante ácidas em relação a ela. Mas ao invés de mal dissermos delas, eu resolvi fazer algo a respeito, oferencendo a minha mentoria.&lt;/p&gt;
&lt;p&gt;É aqui que começa a minha grande promessa:&lt;/p&gt;
&lt;h2&gt;Trazer até você as mesmas estratégias e recursos utilizadas pelos melhores programadores do mundo, Com uma diferença enorme: de maneira simples, acessível e pronta para ser colocada em prática.&lt;/h2&gt;
&lt;p&gt;Se eu fosse fazer uma mentoria personalizada, com reuniões e acompanhamento, isso sairia por milhares de reais 😞 e eu só teria a oportunidade de levar esse conhecimento a pouquíssimas pessoas. Então optei por colocar a um preço extremamente barato, o conhecimento de tudo o que deu certo mentorando os outros pupilos em um único documento, para você fazer no seu tempo!&lt;/p&gt;
&lt;p&gt;CHEGA DE PAPO, clique na foto para acessar os detalhes deste guia!&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;http://bit.ly/guia-dev-autodidata&quot;&gt;&lt;img src=&quot;https://media-exp1.licdn.com/dms/image/C4E12AQGjObVVjSeOMA/article-inline_image-shrink_1000_1488/0/1605780884587?e=1615420800&amp;#x26;v=beta&amp;#x26;t=qVh2v-RZsIvdXVrr5LUK2wTWvQds_oDWjhYdX6BlzGo&quot; alt=&quot;No alt text provided for this image&quot;&gt;&lt;/a&gt;&lt;/p&gt;
&lt;h2&gt;&lt;a href=&quot;https://bit.ly/guia-dev-autodidata&quot;&gt;Lá eu abro o jogo sobre o que funciona e o que não funciona, e o caminho que eu gostaria de ter seguido.&lt;/a&gt;&lt;/h2&gt;
&lt;p&gt;Absolutamente tudo que aprendi ao longo dos 11 anos que trabalhei como programador, além de dizer exatamente como funciona o mercado, e como sair da fase de programador-recém-formado-perdido-na-carreira até o sucesso que você almeja.&lt;/p&gt;
&lt;p&gt;Mas pagar o preço de uma pizza por um PDF? Parece uma idéia maluca, não? Mas este conteúdo transformou a vida de milhares de pessoas (e não sou eu que estou falando, leia os comentários ali embaixo 👇👇), e você tem 7 dias para reembolso (te devolvo o dinheiro sem fazer perguntas) caso entenda que não se encaixe ao seu momento, contexto e objetivos.&lt;/p&gt;
&lt;p&gt;Eu estou escrevendo isto pois recebi essa mensagem no Instagram:&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://media-exp1.licdn.com/dms/image/C4E12AQHDZWdlYn1D-A/article-inline_image-shrink_1000_1488/0/1605781094923?e=1615420800&amp;#x26;v=beta&amp;#x26;t=J1_MCYWk5KagcblRnrdwSNH1Pp4C7efe62p1zwaUbeQ&quot; alt=&quot;No alt text provided for this image&quot;&gt;&lt;/p&gt;
&lt;p&gt;Eu cobro um valor simbólico por um motivo:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Quando você paga por algo, você tende a realizar, quando algo é gratuito você ignora e posterga&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;E não estou nesse jogo por dinheiro, estou para gerar ação e resultados, então se você não tem coragem de me pagar uma pizza de calabreza, e de dar o próximo passo para colocar em prática tudo o que eu falo, eu é que não quero te mentorar, feche essa página e &lt;a href=&quot;https://bit.ly/video-de-brigas&quot;&gt;vá ver gente brigando no twitter&lt;/a&gt;.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Mas se tu quer mudar sua realidade de verdade, é esforçado, mas ainda se sente perdido e ‘não está preparado para o mercado’, cola com o pai que eu vou mover o mundo por você.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;(Se o seu problema é você ser realmente pobre e não tem condições nenhuma, me mande uma &lt;a href=&quot;http://bit.ly/pauloluan-insta&quot;&gt;mensagem no Instagram&lt;/a&gt; que eu te envio de graça, 0800 na faixa, de gratis)&lt;/p&gt;
&lt;p&gt;BORA CODAR.&lt;/p&gt;</content:encoded></item><item><title><![CDATA[Como fazer perguntas sobre programação na internet? (e aumentar 5x as chances de ter uma resposta)]]></title><description><![CDATA[Dicas iniciais Antes de começarmos: Você se sente perdido? Ansioso? A faculdade parece que não te formou direito? As vagas exigem milhares…]]></description><link>https://blog.reativa.dev/como-fazer-perguntas-inteligentes/</link><guid isPermaLink="false">https://blog.reativa.dev/como-fazer-perguntas-inteligentes/</guid><pubDate>Sun, 03 Jan 2021 00:00:00 GMT</pubDate><content:encoded>&lt;h3&gt;Dicas iniciais&lt;/h3&gt;
&lt;p&gt;Antes de começarmos: Você se sente perdido? Ansioso? A faculdade parece que não te formou direito? As vagas exigem milhares de coisas e você se sente um bosta? Eu posso te mentorar! diariamente faço mentoria coletiva (gratuita) para programadores iniciantes que se sentem perdidos, você será extremamente bem vindo por lá (é só clicar na imagem).&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;http://bit.ly/pauloluan-insta&quot;&gt;&lt;img src=&quot;https://media-exp1.licdn.com/dms/image/C4E12AQF9pxdMEVTSQg/article-inline_image-shrink_1500_2232/0/1614414726929?e=1619654400&amp;#x26;v=beta&amp;#x26;t=ti7w8kAyqaK7PRcB9YGnRNv8ircAgThraVR-O1D4T54&quot; alt=&quot;Mentoria Gratuita&quot;&gt;&lt;/a&gt;&lt;/p&gt;
&lt;h3&gt;Aperte &lt;code class=&quot;language-text&quot;&gt;ctrl+p&lt;/code&gt; e imprima esse artigo, para que você possa fazer anotações!&lt;/h3&gt;
&lt;blockquote&gt;
&lt;p&gt;Texto original em &lt;a href=&quot;http://www.catb.org/esr/faqs/smart-questions.html&quot;&gt;inglês&lt;/a&gt;&lt;/p&gt;
&lt;/blockquote&gt;
&lt;blockquote&gt;
&lt;p&gt;Nota sobre o texto: O autor original é um pouco ‘rude’ com alguns termos, tente ignorar esse fato e se atente aos ensinamentos principais (que são extremamente úteis), boa leitura!&lt;/p&gt;
&lt;/blockquote&gt;
&lt;h2&gt;Introdução&lt;/h2&gt;
&lt;p&gt;No mundo dos &lt;em&gt;programadores&lt;/em&gt;, o tipo de respostas que você obtém para suas questões técnicas depende bastante da forma que você faz as perguntas bem como da dificuldade de desenvolver a resposta. Este guia irá ensinar você como fazer perguntas de forma a obter uma resposta satisfatória.&lt;/p&gt;
&lt;p&gt;A primeira coisa a entender é que os &lt;em&gt;programadores&lt;/em&gt; gostam de problemas difíceis e questões boas e provocantes sobre eles. Se não fosse assim, não estaríamos aqui. Se você nos der uma questão interessante para mastigar seremos gratos; boas questões são um estímulo e um presente. Boas perguntas nos ajudam a desenvolver nosso entendimento, e geralmente revelam problemas que poderíamos não ter percebido ou pensado de outra forma. Entre os &lt;em&gt;programadores&lt;/em&gt;, “Boa pergunta!” é um forte e sincero cumprimento.&lt;/p&gt;
&lt;p&gt;Apesar disto, os &lt;em&gt;programadores&lt;/em&gt; tem uma reputação de abordar questões simples com o que se parece com hostilidade ou arrogância. Às vezes parece que somos hostis aos novatos e ignorantes. Mas isto não é verdade.&lt;/p&gt;
&lt;p&gt;O que nós somos, sem qualquer desculpa, é hostis a pessoas que parecem não estar querendo pensar ou fazer seu próprio trabalho de casa antes de fazer perguntas. Pessoas assim são como precipícios — eles pegam sem dar nada em troca, eles desperdiçam um tempo que poderíamos ter usado em outra questão mais interessante e com outra pessoa que valha mais a pena responder. Chamamos este tipo de pessoa de ”&lt;em&gt;losers&lt;/em&gt;” (e por razões históricas às vezes escrevemos ”&lt;em&gt;lusers&lt;/em&gt;”).&lt;/p&gt;
&lt;p&gt;Somos, em grande parte, voluntários. Tomamos tempo de nossas vidas ocupadas, e às vezes somos sobrecarregados por ela. Por isto filtramos as perguntas de forma rude. Em particular, jogamos fora questões de pessoas que pareçam ser &lt;em&gt;losers&lt;/em&gt; para gastar nosso tempo de responder perguntas de forma mais eficiente, com vencedores.&lt;/p&gt;
&lt;p&gt;Você não quer ser um dos &lt;em&gt;losers&lt;/em&gt;. Você não quer parecer com um, também. A melhor forma de conseguir respostas rápidas é fazer as perguntas como um vencedor — perguntar como uma pessoa esperta, confiante, e com dicas, que parece precisar de ajuda apenas em um problema particular.&lt;/p&gt;
&lt;h2&gt;Antes de Perguntar&lt;/h2&gt;
&lt;p&gt;Antes de fazer uma pergunta técnica por email, ou em um &lt;em&gt;newsgroup&lt;/em&gt;, ou em um &lt;em&gt;chat-board&lt;/em&gt; de um &lt;em&gt;website&lt;/em&gt;, faça o seguinte:&lt;/p&gt;
&lt;ol&gt;
&lt;li&gt;Tente encontrar uma resposta lendo o manual&lt;/li&gt;
&lt;li&gt;Tente encontrar uma resposta lendo o FAQ&lt;/li&gt;
&lt;li&gt;Tente encontrar uma resposta pesquisando a Web&lt;/li&gt;
&lt;li&gt;Tente encontrar uma resposta perguntando a algum amigo mais preparado&lt;/li&gt;
&lt;/ol&gt;
&lt;p&gt;Quando fizer sua pergunta, mostre que você fez estas coisas primeiro, isto ajuda a estabelecer que você não está sendo uma esponja preguiçosa e desperdiçando o tempo de outras pessoas. Melhor ainda, mostre que você aprendeu alguma coisa tendo feito estas coisas. Gostamos de responder perguntas de pessoas que tenham demonstrado que podem aprender das respostas.&lt;/p&gt;
&lt;p&gt;Prepare sua questão. Pense adiante. Perguntas que pareçam precipitadas recebem respostas precipitadas, ou nenhuma resposta. Quanto mais você demonstrar que dedicou pensamentos e esforços em resolver seu problema antes de pedir por ajuda, mais provável é que você vá conseguir ajuda.&lt;/p&gt;
&lt;p&gt;Cuidado para não fazer a pergunta errada. Se você fizer perguntas baseadas em pressupostos falsos, &lt;em&gt;J. Random&lt;/em&gt; provavelmente vai responder com uma resposta literalmente inútil ao mesmo tempo que pensa “Pergunta estúpida…”, e com a esperança de que a experiência de ganhar o que você pediu em vez do que você precisa vá lhe ensinar uma lição.&lt;/p&gt;
&lt;p&gt;Por outro lado, tornar claro que você está apto e pronto a ajudar no processo de desenvolver a solução é um bom início. “Alguém pode me providenciar uma dica?”, “O que falta no meu exemplo?” e “Existe algum site que eu deveria ter procurado?” são perguntas que provavelmente vão ter respostas, em vez de “Por favor poste o procedimento que devo usar.” por que neste caso você está tornando claro que você não está disposto a completar o processo se alguém puder simplesmente apontar a direção certa para você.&lt;/p&gt;
&lt;p&gt;Nunca assuma que você tem direito a uma resposta. Você não tem. Você vai conquistar uma resposta se puder conquistar a mesma, fazendo uma pergunta que seja substancial, interessante, estimulante — uma que implicitamente contribua à experiência da comunidade em vez de meramente exigir passivamente por conhecimentos dos outros.&lt;/p&gt;
&lt;h2&gt;Quando Perguntar&lt;/h2&gt;
&lt;h3&gt;Escolha seu fórum cuidadosamente&lt;/h3&gt;
&lt;p&gt;Seja perceptivo ao escolher onde fazer sua pergunta. Você tem mais chances de ser ignorado, ou chamado de &lt;em&gt;loser&lt;/em&gt;, se:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;postar sua pergunta em um fórum no qual ela seja &lt;em&gt;off topic&lt;/em&gt;&lt;/li&gt;
&lt;li&gt;postar uma pergunta muito elementar onde sejam esperadas questões técnicas avançadas, ou vice-versa&lt;/li&gt;
&lt;li&gt;fizer &lt;em&gt;cross-post&lt;/em&gt; para muitos &lt;em&gt;newsgroups&lt;/em&gt; diferentes&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Os &lt;em&gt;programadores&lt;/em&gt; detonam com perguntas que sejam feitas inapropriadamente para tentar proteger seus canais de comunicação de serem afogados em irrelevâncias. Você não vai querer que isto aconteça com você.&lt;/p&gt;
&lt;h3&gt;Escreva em linguagem clara, gramática e ortograficamente correta&lt;/h3&gt;
&lt;p&gt;Sabemos por experiência que pessoas que são escritores descuidados e superficiais são também geralmente pensadores descuidados e superficiais (com experiência suficiente para apostar nisto). Responder perguntas para pensadores descuidados e superficiais não traz nenhuma compensação; nós preferimos gastar nosso tempo com outras coisas.&lt;/p&gt;
&lt;p&gt;Portanto, expressar sua dúvida de forma clara e correta é importante. Se você não pode se incomodar com isto, nós não podemos nos incomodar em prestar atenção. Gaste algum esforço extra para polir sua linguagem. Você não precisa ser cerimonioso ou formal — ao contrário, a cultura dos &lt;em&gt;programadores&lt;/em&gt; valoriza a linguagem informal, cheia de gírias e humor, usada com precisão. Mas ela precisa ser precisa; tem que haver algum indício que você está pensando e prestando atenção.&lt;/p&gt;
&lt;p&gt;Escreva corretamente. Não confunda ”&lt;em&gt;its&lt;/em&gt;” com ”&lt;em&gt;it’s&lt;/em&gt;”, ou ”&lt;em&gt;loose&lt;/em&gt;” com ”&lt;em&gt;lose&lt;/em&gt;”. Não escreva TUDO EM MAIÚSCULAS, isto é lido como um grito e considerado rude. Se você escreve como um bobo semi-analfabeto, provavelmente você será ignorado. Escrever como um &lt;em&gt;l33t script kiddie hax0r&lt;/em&gt; é o beijo da morte e garante que você não receberá nada a não ser um silêncio pétreo (ou, na melhor das hipóteses, ajuda carregada de desprezo e sarcasmo).&lt;/p&gt;
&lt;p&gt;Se você está fazendo perguntas em um fórum que não usa sua linguagem nativa, você vai ter uma quantia limitada de tolerância a erros ortográficos e gramaticais — mas nenhuma tolerância a prequiça mental. Além disso, a menos que você saiba a linguagem de quem vai te responder, escreva em inglês. &lt;em&gt;programadores&lt;/em&gt; ocupados tendem a simplesmente ignorar questões em linguagens que eles não entendem, e o inglês é a linguagem de trabalho na Internet. Escrevendo as perguntas em inglês você minimiza as chances de que as mesmas sejam descartadas sem ser lidas.&lt;/p&gt;
&lt;h3&gt;Envie questões em formatos que sejam fáceis de entender&lt;/h3&gt;
&lt;p&gt;Se você faz questões artificialmente difíceis de ler, provavelmente será ignorado em favor de alguém que não faz isto. Portanto:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Envie email em texto puro, não HTML&lt;/li&gt;
&lt;li&gt;Não envie emails em que os parágrafos inteiros sejam linhas únicas (isto torna mais difícil responder a somente uma parte da mensagem)&lt;/li&gt;
&lt;li&gt;Nunca, jamais espere que os &lt;em&gt;programadores&lt;/em&gt; possam ler formatos de documentos proprietários fechados como do &lt;em&gt;Microsoft Word&lt;/em&gt;. A maioria dos &lt;em&gt;programadores&lt;/em&gt; reagem a estes formatos da mesma forma que você reagiria a um monte fedorento de esterco de porco jogado na tua porta.&lt;/li&gt;
&lt;li&gt;Se você estiver enviando email em uma máquina Windows, retire a funcionalidade estúpida de ”&lt;em&gt;Smart Quotes&lt;/em&gt;” da Microsoft. Fazendo isto você evita pingar caracteres inúteis em seu email&lt;/li&gt;
&lt;/ul&gt;
&lt;h3&gt;Utilize linhas de assunto com significado e específicas&lt;/h3&gt;
&lt;p&gt;Em listas de correio ou grupos de notícias, a linha de assunto é sua oportunidade de ouro para atrair a atenção de especialistas qualificados em cerca de 50 caracteres ou menos. Não desperdice esta oportunidade com murmúrios e balbúcias, como “Por favor me ajudem” (ou então “POR FAVOR ME AJUDEM!!!!”). Não tente nos impressionar com a profundidade de tua angústia; ao invés disto, use o espaço para uma descrição super-concisa do problema.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Estúpida:&lt;/strong&gt;&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;SOCORRO! O vídeo não funciona no meu laptop!&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;strong&gt;Inteligente:&lt;/strong&gt;&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;XFree86 4.1 mostra cursor errado, chipset de vídeo Fooware MV1005&lt;/li&gt;
&lt;/ul&gt;
&lt;h3&gt;Seja preciso e informativo sobre o seu problema&lt;/h3&gt;
&lt;ul&gt;
&lt;li&gt;Descreva os sintomas do seu problema ou &lt;em&gt;bug&lt;/em&gt; cuidadosa e claramente.&lt;/li&gt;
&lt;li&gt;Descreva o ambiente em que o mesmo ocorre (máquina, SO, aplicação, o que for)&lt;/li&gt;
&lt;li&gt;Descreva a pesquisa que você fez para experimenta resolver e entender o problema antes de ter feito a pergunta&lt;/li&gt;
&lt;li&gt;Descreva os passos de diagnóstico que você tomou para resolver o problema por conta própria antes de ter feito a pergunta&lt;/li&gt;
&lt;li&gt;Descreva qualquer alteração recente no seu computador ou configuração de software que possa ser relevante&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Faça o melhor que puder para antecipar as perguntas que um &lt;em&gt;programador&lt;/em&gt; possa fazer, e para responder as mesmas previamente no seu pedido de ajuda.&lt;/p&gt;
&lt;p&gt;Simon Tatham escreveu um excelente documento chamado &lt;em&gt;How to Report Bugs Effectively&lt;/em&gt;. Eu recomendo que você leia o mesmo.&lt;/p&gt;
&lt;h3&gt;Descreva os Sintomas, não suas suspeitas&lt;/h3&gt;
&lt;p&gt;Não há utilidade em dizer aos &lt;em&gt;programadores&lt;/em&gt; o que você pensa que está causando seu problema (se suas teorias de diagnósticos fossem tão boas, você estaria pedindo ajuda?). Assim, certifique-se de informar os sintomas exatos do que está dando errado, em vez de suas interpretações e teorias. Deixe-os fazer a interpretação e diagnóstico.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Estúpida:&lt;/strong&gt;&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Estou tendo erros SIG11 quando o kernel compila, e suspeito que uma trilha da motherboard está interrompida. Qual a melhor forma de verificar isto?&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;strong&gt;Inteligente:&lt;/strong&gt;&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Meu computador feito em casa K6/233 com mobo FIC-PA2007 (chipset VIA Apollo VP2) com 256MB SDRAM Corsair PC133 começa a dar erros SIG11 frequentes cerca de 20 minutos após ser ligada, durante compilações de kernel, mas nunca nos primeiros 20 minutos. Reinicializar não reinicia o relógio, mas desligar à noite sim. Trocar toda a RAM não ajudou. O trecho relevante de um log de uma sessão de compilação típica segue abaixo.&lt;/li&gt;
&lt;/ul&gt;
&lt;h3&gt;Descreva os sintomas dos problemas em ordem cronológica&lt;/h3&gt;
&lt;p&gt;As pistas mais úteis para descobrir o que está errado geralmente estão no que ocorreu um pouco antes. Por isto, descreva precisamente o que você fez, e o que a máquina fez, até a ocorrência do problema. No caso de processos de linha de comando, ter um log da sessão (por exemplo usando o utilitário script) e copiando as vinte e tantas linhas relevantes é bastante útil.&lt;/p&gt;
&lt;p&gt;Se o programa que está dando problemas possui opções de diagnóstico (tipo uma opção -v para modo verboso), tente pensar com carinho em usar algumas opções que possam acrescentar alguma informação de depuração úteis ao texto transcrito.&lt;/p&gt;
&lt;p&gt;Se sua mensagem for muito longa (mais que cerca de quatro parágrafos), pode ser útil descrever o problema de forma sucinta no início, e então seguir com a história cronológica. Desta forma, os &lt;em&gt;programadores&lt;/em&gt; saberão o que procurar quando estiverem lendo sua crônica.&lt;/p&gt;
&lt;h3&gt;Não peça para ser respondido via email privado&lt;/h3&gt;
&lt;p&gt;Os &lt;em&gt;programadores&lt;/em&gt; acreditam que a solução de problemas deve ser um processo público e transparente, durante o qual uma primeira tentativa de resposta pode e deve ser corrigida por alguém com mais conhecimentos que tenha percebido que a mesma está incompleta ou incorreta. Da mesma forma, eles obtém alguma recompensa por ter respondido por serem vistos como competentes e conhecedores por seus iguais.&lt;/p&gt;
&lt;p&gt;Quando você pede uma resposta em private, você está interrompendo tanto o processo quanto o prêmio. Não faça isto. É escolha de quem responde se a resposta deve seguir em &lt;em&gt;private&lt;/em&gt; — e se isto acontece, usualmente é por que ele pensa que a questão é muito óbvia ou mal-formada para interessar a outros.&lt;/p&gt;
&lt;p&gt;Há uma exceção limitada a esta regra. Se você pensa que a questão é tal que você provavelmente vai receber muitas respostas que são muito semelhantes, então as palavras mágicas são “mandem por email que eu resumo as respostas para o grupo”. É cortês tentar proteger a lista de mail e o &lt;em&gt;newsgroup&lt;/em&gt; de uma inundação de &lt;em&gt;posts&lt;/em&gt; idênticos — mas você deve cumprir a promessa de mandar o resumo.&lt;/p&gt;
&lt;h3&gt;Corte fora perguntas inúteis&lt;/h3&gt;
&lt;p&gt;Resista a tentação de fechar seu pedido de ajuda com questões semanticamentes nulas como “Alguém pode me ajudar?” ou “Há alguma resposta?” Primeiro, se você fez sua parte da descrição do problema de forma competente, este tipo de pergunta é, na melhor hipótese, supérflua. Em segundo, pelo que a precede, esta questão beira a perturbação, convidando a respostas inúteis mas lógicamente impecáveis como “Sim” ou “Não”. Cortesia não machuca, e, às vezes, ajuda&lt;/p&gt;
&lt;p&gt;Seja cortês. Use “Por favor”, e “Agradeço antecipadamente”. Torne claro que você dá valor ao tempo que as pessoas gastam tentando te ajudar gratuitamente.&lt;/p&gt;
&lt;p&gt;Para ser honesto, isto não é tão importante quanto (e não é susbtituto de) ser gramaticalmente correto, claro, preciso e descritivo, evitando formatos proprietários, etc. Os &lt;em&gt;programadores&lt;/em&gt; em geral perferem um relatório de bugs um tanto brusco mas técnicamente correto, que uma mensagem polidamente vaga (se isto te surpreende, lembre que damos valor a uma questão pelo que ela nos ensina).&lt;/p&gt;
&lt;p&gt;Entretanto, se você tem os fatos técnicos citados coerentemente, ser polido aumenta as chances de conseguir uma resposta útil.&lt;/p&gt;
&lt;h3&gt;Poste uma mensagem curta apontando a solução encontrada&lt;/h3&gt;
&lt;p&gt;Envie uma nota após o problema ter sido solucionado para todos que te ajudaram; deixe-os saberem como ficou e agradeça novamente pela ajuda. Se o problema atraiu o interesse geral na lista de email ou &lt;em&gt;newsgroup&lt;/em&gt;, é apropriado postar um retorno no mesmo.&lt;/p&gt;
&lt;p&gt;O &lt;em&gt;follow-up&lt;/em&gt; não precisa ser longo e detalhado, um simples “Feito - era um cabo de rede com problemas! Obrigado a todos - Bill” é melhor que nada. De fato, um resumo curto e simples é melhor que uma longa dissertação a menos que a resposta tenha um real valor técnico.&lt;/p&gt;
&lt;p&gt;Além de ser cortês e informativo, este tipo de &lt;em&gt;follow-up&lt;/em&gt; ajuda todo mundo que deu assistência a ter uma sensação de fechamento do problema. Se você não é um &lt;em&gt;techie&lt;/em&gt; ou &lt;em&gt;programador&lt;/em&gt;, acredite em nós que este sentimento é muito importante para os gurus e especialistas que você pediu ajuda. Narrativas de problemas que terminam em um vazio não resolvido são coisas frustrantes; os &lt;em&gt;programadores&lt;/em&gt; sentem uma comichão por ver os mesmos resolvidos. O bom karma que você ganha coçando esta comichão é que será muito mais útil postar uma pergunta na próxima vez que você tiver algum problema.&lt;/p&gt;
&lt;h2&gt;Como Interpretar as Respostas&lt;/h2&gt;
&lt;h3&gt;RTFM e STFW: Como Saber que Você “se Ferrou”&lt;/h3&gt;
&lt;p&gt;Há uma tradição antiga e respeitada: se você recebe uma resposta escrita “RTFM”, a pessoa que enviou pensa que você deve Ler O Diabo do Manual (”&lt;em&gt;Read The Fucking Manual&lt;/em&gt;” - a expressão é mais “colorida” no original). E ele provavelmente está certo sobre isto. Vá ler o manual.&lt;/p&gt;
&lt;p&gt;RTFM tem um parente mais jovem. Se você receber uma resposta “STFW”, a pessoa que mandou ela pensa que você deveria Procurar no Diabo da Web (”&lt;em&gt;Search The Fucking Web&lt;/em&gt;”). E ele provavelmente está certo sobre isto. Vá fazer uma pesquisa.&lt;/p&gt;
&lt;p&gt;Geralmente, a pessoa que envia um destas respostas tem o manual ou a página com a informação que você precisa aberta, e está olhando para ela enquanto escreve. Estas respostas significam que (a) a informação a ler é fácil de encontrar, e (b) você vai aprender mais se procurar por conta própria do que se você ganhar a mesma de mão beijada.&lt;/p&gt;
&lt;p&gt;Você não deve se sentir ofendido por estas respostas - pelos padrões dos &lt;em&gt;programadores&lt;/em&gt;, ele está te mostrando um pouco de respeito simplesmente por não ter te ignorado. Você deveria, ao invés, ficar agradecido pela sua bondade de vovózinha.&lt;/p&gt;
&lt;h3&gt;Se você não entendeu…&lt;/h3&gt;
&lt;p&gt;Se você não entendeu a resposta, não devolva imediatamente um pedido de esclarecimento. Use as mesmas ferramentas que você usou para encontrar uma resposta para sua pergunta original (manuais, FAQ, a Web, um amigo que saiba mais) para entender a resposta. Se você precisar mais esclarecimentos, mostre o que você aprendeu.&lt;/p&gt;
&lt;p&gt;Por exemplo, suponha que eu tenha dito: “Parece que você tem uma zentry presa, você precisa limpar ela.” Então:&lt;/p&gt;
&lt;p&gt;Eis uma pergunta ruim: “O que é uma zentry?”&lt;/p&gt;
&lt;p&gt;Eis uma pergunta boa: “OK, eu li a página man e as zentries são mencionadas somente sob as opções -z e -p. Nenhuma delas esclarece nada sobre zentries. É só isto ou eu estou deixando passar alguma coisa aqui?”&lt;/p&gt;
&lt;h3&gt;Não Reaja como um Perdedor&lt;/h3&gt;
&lt;p&gt;Eventualmente você vai se dar mal algumas vezes em fóruns da comunidade de &lt;em&gt;programadores&lt;/em&gt; — em formas detalhadas neste artigo, ou parecidas. E vai ser dito para você exatamente onde você se deu mal, possivelmente com termos coloridos. Em público.&lt;/p&gt;
&lt;p&gt;Quando isto acontecer, a pior coisa que você pode fazer é se queixar da experiência, alegar ter sido verbalmente atacado, exigir que se desculpem, gritar, prender a respiração, ameaçar com processos legais, reclamar com os chefes das pessoas, deixar a tampa do vaso levantada, etc. Ao invés disso, aqui está o que você deve fazer:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Supere isto. É normal. De fato, é saudável e apropriado.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Os padrões da comunidade não se mantém por si mesmos: eles são mantidos por pessoas que ativamente os aplicam, visivelmente, em público. Não se queixe que toda crítica deveria ir por email privado: não é assim que isto funciona. Nem é útil insistir que você foi insultado pessoalmente quanto alguém comentar que algumas de suas alegações estão erradas, ou que ele vê de forma diferente. Estas são atitudes de perdedores.&lt;/p&gt;
&lt;p&gt;Tem havido forums de &lt;em&gt;programadores&lt;/em&gt; onde, por conta de algum senso de hiper-cortesia mal orientado, os participantes são banidos por postar qualquer mensagem apontando erros de outros, e ouvem um “Não diga nada se você não está a fim de ajudar o usuário”. A resultantes partida de participantes que sabiam alguma coisa para outros lugares causou a queda do grupo para uma balbúrdia sem sentido e os tornou inúteis como fóruns técnicos.&lt;/p&gt;
&lt;h3&gt;Exageradamente “amigável” (daquele jeito) ou útil: escolha.&lt;/h3&gt;
&lt;p&gt;Lembre-se: quando aquele &lt;em&gt;programador&lt;/em&gt; te disser que você errou, e (não importa o quão rude) te diz para não fazer isto novamente, ele está agindo por preocupação (1) por ti e (2) pela comunidade. Seria mais fácil para ele ignorar você e filtrar você fora da vida dele. Se você não consegue ser grato, pelo menos tenha um pouco de dignidade, não chore, e não espere ser tratado como uma boneca frágil só por que você é um novato com uma alma teatralmente hipersensível e ilusões de merecimento.&lt;/p&gt;
&lt;h2&gt;Perguntas Que Não Se Faz&lt;/h2&gt;
&lt;p&gt;Aqui estão algumas perguntas estúpidas clássicas, e o que os &lt;em&gt;programadores&lt;/em&gt; estão pensando quando não respondem às mesmas.&lt;/p&gt;
&lt;h3&gt;P: Onde eu encontro o programa X?&lt;/h3&gt;
&lt;p&gt;&lt;strong&gt;R&lt;/strong&gt;: No mesmo lugar em que eu encontrei ele, bobão — na outra ponta de uma pesquisa na web. D’eus, ninguém sabe usar o Google ainda?&lt;/p&gt;
&lt;h3&gt;P: Estou tendo problemas com minha máquina Windows. Você pode me ajudar?&lt;/h3&gt;
&lt;p&gt;&lt;strong&gt;R&lt;/strong&gt;: Sim. Jogue fora aquele lixo da Microsoft e instale o Linux.&lt;/p&gt;
&lt;h3&gt;P: Estou tendo problemas para instalar o Linux ou o X. Você pode me ajudar?&lt;/h3&gt;
&lt;p&gt;&lt;strong&gt;R&lt;/strong&gt;: Não. Eu preciso ter acesso à tua máquina para resolver este problema. Vá pedir ajuda no teu grupo de usuários Linux local.&lt;/p&gt;
&lt;h3&gt;P: Como eu posso crackear o root/roubar privilégios de ops de canais/ler os emails de outra pessoa?&lt;/h3&gt;
&lt;p&gt;&lt;strong&gt;R&lt;/strong&gt;: Você é uma forma de vida inferior por querer fazer este tipo de coisa e um debilóide por pedir que um &lt;em&gt;programador&lt;/em&gt; te ajude.&lt;/p&gt;
&lt;h2&gt;Boas e Más Perguntas&lt;/h2&gt;
&lt;p&gt;Por fim, vou ilustrar como fazer perguntas de uma forma inteligente por exemplo. Pares de questões sobre o mesmo problema, uma pergunta feita de forma estúpida, e outra de forma inteligente.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Estúpida:&lt;/strong&gt; Onde eu posso encontrar alguma informação sobre o Foonly Flubarmatic?&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Esta pergunta está implorando por um “STFW” como resposta.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;strong&gt;Inteligente&lt;/strong&gt;: Eu usei o Google para pesquisar por “Foonly Flubarmatic 2600” na Web, mas não consegui nenhum link útil. Alguém sabe onde eu posso encontrar alguma informação sobre a programação deste dispositivo?&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Este usuário já SFTW ou, e parece que ele tem um problema real.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;strong&gt;Estúpida&lt;/strong&gt;: Não consigo compilar o projeto foo. Por quê ele está com erros?&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Ele está assumindo que todo mundo está errado. Arrogância da parte dele.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;strong&gt;Inteligente&lt;/strong&gt;: O código do projeto foo não compila no Nulix versão 6.2. Eu li o FAQ, mas não tem nada sobre problemas relacionados ao Nulix. Aqui tem uma transcrição de minhas tentativas de compilar o mesmo, é algo que eu fiz?&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Ele especificou o ambiente, ele leu o FAQ, ele está mostrando o erro, e ele não está assumindo que seu problema é por causa do erro de outra pessoa. Este cara merece alguma atenção.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;strong&gt;Estúpida:&lt;/strong&gt; Estou tendo problemas com minha motherboard. Alguém pode me ajudar?&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;A resposta de &lt;em&gt;J. Random&lt;/em&gt; é provavelmente “Certo. Precisa arrotar e trocar as fraldas também?” seguido pelo pressionar da tecla delete.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;strong&gt;Inteligente:&lt;/strong&gt; Eu tentei X, Y e Z na motherboard S2464. Quando isto não funcionou, eu tentei A, B e C. Note o sintoma curioso quando tentei C. Obviamente o florbish está gromicando, mas os resultados não são os esperados. Quais são as causas usuais de gromicamento em motherboards MP? Alguém tem idéias de testes que eu possa fazer para descobrir o problema?&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;
&lt;p&gt;Esta pessoa, por outro lado, parece que vale a pena responder. Ela exibiu inteligência para resolver problemas ao invés de ficar esperando que uma solução caísse do céu. Na última questão, note a sutil mas importante diferença entre “Me dê uma resposta” e “por favor me ajude a descobrir que diagnósticos adicionais posso tentar para descobrir o problema”. De fato, a forma da última questão é baseada em um incidente real que aconteceu em agosto de 2001 na lista de correio linux-kernel. Eu era quem estava fazendo a pergunta aquela vez. Eu estava observando misteriosos travamentos em uma motherboard Tyan S2464. Os membros da lista forneceram as informações que eu precisava para resolver o problema. Fazendo a pergunta do jeito que eu fiz, eu dei algo para que as pessoas mastigassem, eu tornei fácil e atrativo o envolvimento. Eu demonstrei respeito pela habilidade de meus colegas e convidei eles a me consultarem como a um igual. Eu demonstrei respeito pelo tempo deles informando quais as ruas escuras que eu já havia tomado. Mais tarde, quando agradeci a todos e destaquei como o processo funcionou bem, um membro da lkml apontou que ele pensava que o processo funcionou não por que eu era um “nome” naquela lista, mas por que eu fiz a pergunta de forma apropriada.&lt;/p&gt;
&lt;p&gt;Nós, &lt;em&gt;programadores&lt;/em&gt;, estamos, de certa forma, em uma rude meritocracia: estou certo que ele está correto, e seu eu tivesse agido como uma esponja eu teria recebido &lt;em&gt;flames&lt;/em&gt; ou seria ignorado, não importando quem eu era. Sua sugestão que eu escrevesse sobre o incidente como uma instrução para outros foi o que me inspirou a compor este guia.&lt;/p&gt;
&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;Considerações finais&lt;/h2&gt;
&lt;p&gt;Agradecimentos: texto original foi escrito por &lt;em&gt;Por: Eric Raymond&lt;/em&gt; em inglês: &lt;a href=&quot;http://www.catb.org/esr/faqs/smart-questions.html&quot;&gt;http://www.catb.org/esr/faqs/smart-questions.html&lt;/a&gt; &lt;em&gt;Tradução feita por: &lt;a href=&quot;http://geocities.yahoo.com.br/cesarakg/&quot;&gt;César A. K. Grossmann&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;
&lt;p&gt;Evelyn Mitchell contribuiu com alguns exemplos de perguntas estúpidas e inspirou a seção “Como responder perguntas de forma útil”. Mikhail Ramendik contribuiu com valiosas sugestões de aprimoramento deste guia.&lt;/p&gt;
&lt;h2&gt;Como responder perguntas de forma útil&lt;/h2&gt;
&lt;p&gt;Seja gentil. Stress relacionado a problemas podem fazer as pessoas parecerem rudes ou estúpidas mesmo que elas não sejam.&lt;/p&gt;
&lt;p&gt;Responda à uma primeira falta offline. Não há necessidade de humilhar publicamente alguém que tenha honestamente cometido um erro. Um novato de verdade pode não saber como pesquisar o histórico da lista ou onde o FAQ está localizado.&lt;/p&gt;
&lt;p&gt;Se você não tem certeza, deixe isto claro! Uma resposta errada mas cheia de autoridade é pior do que nenhuma resposta. Não indique a ninguém um caminho errado só porque é divertido falar como um expert. Seja humilde e honesto; dê um bom exemplo para os seus companheiros.&lt;/p&gt;
&lt;p&gt;Se você não pode ajudar, não atrapalhe! Não faça piadas sobre procedimentos que podem bagunçar o sistema do usuário — o pobre coitado pode interpretar isto como instruções sérias.&lt;/p&gt;
&lt;p&gt;Faça perguntas para levantar mais informações. Se você for bom nisso o usuário irá aprender alguma coisa — e talvez você também. Tente transformar uma pergunta ruim em uma pergunta boa; lembre-se que todos nós fomos novatos um dia.&lt;/p&gt;
&lt;p&gt;Enquanto mandar um RTFM é algumas vezes justificável quando você está respondendo uma pergunta de um preguiçoso, uma indicação do local exato da documentação (ou a frase correta para pesquisar no Google) é bem melhor.&lt;/p&gt;
&lt;p&gt;Se você for responder uma pergunta, responda direito. Não sugira gambiarras para fazer funcionar a ferramenta errada. Sugira a ferramenta certa. Refaça a pergunta.&lt;/p&gt;
&lt;p&gt;Ajude sua comunidade a aprender com a pergunta. Quando você responder a uma pergunta pense: “Como a documentação ou o FAQ podem ser melhorados para que ninguém precise perguntar isso novamente?” E então envie um patch ao mantenedor da documentação.&lt;/p&gt;
&lt;p&gt;Se você teve que pesquisar para encontrar uma resposta, demonstre como você encontrou a resposta ao invés de fazer parecer que você a tirou de dentro de uma cartola. Responder a uma boa pergunta é como dar um prato de comida a um faminto. Mas ensiná-lo a plantar o próprio alimento é lhe garantir comida para o resto da vida. == Fontes relacionadas ==&lt;/p&gt;
&lt;p&gt;Se você precisa de instruções sobre o básico dos computadores, sistemas Unix e Internet consulte o HOWTO Fundamentos do Unix e da Internet. (em inglês)&lt;/p&gt;
&lt;p&gt;Quando você distribuir um software ou escrever patches para um, tente seguir o guia HOWTO Software Release Practice. (em inglês)&lt;/p&gt;</content:encoded></item><item><title><![CDATA[Apostila de NodeJS 100% Gratuita]]></title><description><![CDATA[Esta apostila é o resultado de alguns meses de pesquisa, revisão e edição, foi baseada na documentação oficial (então as informações são…]]></description><link>https://blog.reativa.dev/apostila-nodejs-completa/</link><guid isPermaLink="false">https://blog.reativa.dev/apostila-nodejs-completa/</guid><pubDate>Sun, 12 Jan 2020 00:00:00 GMT</pubDate><content:encoded>&lt;p&gt;Esta apostila é o resultado de alguns meses de pesquisa, revisão e edição, foi baseada na documentação oficial (então as informações são confiáveis). &lt;/p&gt;
&lt;p&gt;Este conteúdo eu iria colocar no como adicional no &lt;a href=&quot;https://bit.ly/guia-dev-autodidata&quot;&gt;Guia do Dev Autodidata&lt;/a&gt; (que é o meu guia para &lt;strong&gt;iniciantes&lt;/strong&gt;). Mas resolvi deixar &lt;strong&gt;gratuito&lt;/strong&gt; a toda a comunidade, então aproveite e bons estudos!&lt;/p&gt;
&lt;p&gt;Se tiver qualquer dúvida (ou sugestões) me envie no &lt;a href=&quot;http://bit.ly/pauloluan-insta&quot;&gt;Instagram&lt;/a&gt;, faço mentoria coletiva (gratuita) diariamente para programadores iniciantes que se sentem perdidos, você será extremamente bem vindo por lá (é só clicar na imagem).&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;http://bit.ly/pauloluan-insta&quot;&gt;&lt;img src=&quot;https://media-exp1.licdn.com/dms/image/C4E12AQF9pxdMEVTSQg/article-inline_image-shrink_1500_2232/0/1614414726929?e=1619654400&amp;#x26;v=beta&amp;#x26;t=ti7w8kAyqaK7PRcB9YGnRNv8ircAgThraVR-O1D4T54&quot; alt=&quot;Mentoria Gratuita&quot;&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;Um grande abraço, Paulo Luan.&lt;/p&gt;
&lt;h3&gt;Dica: Aperte &lt;code class=&quot;language-text&quot;&gt;ctrl+p&lt;/code&gt; e imprima esse artigo, para que você possa fazer anotações!&lt;/h3&gt;
&lt;h2&gt;Introdução ao Node.js&lt;/h2&gt;
&lt;p&gt;Node.js é um ambiente de execução JavaScript open source e multiplataforma. É uma ferramenta popular para quase todo tipo de projeto!&lt;/p&gt;
&lt;p&gt;Node.js roda na engine (motor) V8, o coração do Google Chrome, fora do navegador. Isso permite que o Node.js seja muito performático.&lt;/p&gt;
&lt;p&gt;Uma aplicação Node.js roda em um único processo, sem criar uma nova thread para cada requisição. O Node.js provê uma série de primitivas assíncronas para I/O (input/output) em sua biblioteca nativa que previnem códigos JavaScript bloqueantes, e geralmente, bibliotecas em Node.js são escritas usando como padrão paradigmas não-bloqueantes, fazendo com que o comportamento de bloqueio seja uma exceção à regra.&lt;/p&gt;
&lt;p&gt;Quando o Node.js executa operações de I/O, como ler dados da rede, acessar um banco de dados ou o sistema de arquivos, em vez de bloquear a thread em execução e gastar ciclos de CPU esperando, o Node.js vai continuar com as operações quando a resposta retornar.&lt;/p&gt;
&lt;p&gt;Isso permite com que o Node.js lide com centenas de conexões paralelas em um único servidor, removendo o fardo de gerenciar concorrências em threads, que podem ser fontes significativas de bugs.&lt;/p&gt;
&lt;p&gt;Node.js tem uma vantagem única poque milhões de desenvolvedores frontend que programam JavaScript para o navegador possam agora desenvolver código server-side (backend) além do client-side (frontend), sem a necessidade de aprender uma linguagem completamente diferente.&lt;/p&gt;
&lt;p&gt;No Node.js os novos padrões do ECMAScript podem ser utilizados sem problemas, como você não precisa esperar todos os seus usuários atualizarem seus navegadores, você tem a liberdade de decidir qual versão do ECMAScript utilizar, bastando trocar a versão do Node.js, além de poder habilitar especificamente features experimentais, bastando executar o Node.Js com as flags apropriadas.&lt;/p&gt;
&lt;h2&gt;Um número imenso de bibliotecas&lt;/h2&gt;
&lt;p&gt;O npm (node package manager) com sua simples estrutura ajudou na ploriferação do ecossistema Node.js, hospedando atualmente mais de 1,000,000 de pacotes open source que podem ser utilizados gratuitamente.&lt;/p&gt;
&lt;h2&gt;Um exemplo de aplicação Node.js&lt;/h2&gt;
&lt;p&gt;O exemplo mais comum de Hello World no Node.js é um servidor web:&lt;/p&gt;
&lt;iframe
  title=&quot;Hello world web server&quot;
  src=&quot;https://glitch.com/embed/#!/embed/nodejs-dev-0001-01?path=server.js&amp;previewSize=30&amp;attributionHidden=true&amp;sidebarCollapsed=true&quot;
  alt=&quot;nodejs-dev-0001-01 on Glitch&quot;
  style=&quot;height: 400px; width: 100%; border: 0;&quot;&gt;
&lt;/iframe&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; http &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;http&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; hostname &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;127.0.0.1&apos;&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; port &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;3000&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; server &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; http&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;createServer&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusCode &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;200&lt;/span&gt;
  res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;setHeader&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Content-Type&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;text/plain&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;end&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hello World\n&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

server&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;listen&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;port&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; hostname&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;Server running at http://&lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;hostname&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;:&lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;port&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;/&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Para executar esse trecho, salve-o como &lt;code class=&quot;language-text&quot;&gt;server.js&lt;/code&gt; e rode com &lt;code class=&quot;language-text&quot;&gt;node server.js&lt;/code&gt; no seu terminal.&lt;/p&gt;
&lt;p&gt;Primeiramente esse código importa o módulo &lt;a href=&quot;https://nodejs.org/api/http.html&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;http&lt;/code&gt;&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;O Node.js tem uma &lt;a href=&quot;https://nodejs.org/api/&quot;&gt;biblioteca padrão&lt;/a&gt; fantástica, incluindo suporte de primeira classe para redes.&lt;/p&gt;
&lt;p&gt;O método &lt;code class=&quot;language-text&quot;&gt;createServer()&lt;/code&gt; do &lt;code class=&quot;language-text&quot;&gt;http&lt;/code&gt; cria um novo servidor HTTP e o retorna.&lt;/p&gt;
&lt;p&gt;É definido para o servidor escutar em uma porta e host name (nome de anfitrião, ao pé da letra) específicos. Quando o servidor está pronto, a função callback é chamada, nesse caso nos informando que o servidor está rodando.&lt;/p&gt;
&lt;p&gt;Sempre que uma nova requisição é recebida, o &lt;a href=&quot;https://nodejs.org/api/http.html#http_event_request&quot;&gt;evento de request&lt;/a&gt; é chamado, provendo dois objetos: uma requisição (objeto do tipo &lt;a href=&quot;https://nodejs.org/api/http.html#http_class_http_incomingmessage&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;http.IncomingMessage&lt;/code&gt;&lt;/a&gt;) e uma resposta (objeto do tipo &lt;a href=&quot;https://nodejs.org/api/http.html#http_class_http_serverresponse&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;http.ServerResponse&lt;/code&gt;&lt;/a&gt;).&lt;/p&gt;
&lt;p&gt;Esses 2 objetos são essenciais para manusear a chamada HTTP.&lt;/p&gt;
&lt;p&gt;O primeiro provê os detalhes da requisição. Nesse simples exemplo, ele não é utilizado, mas com ele você pode acessar os dados da request e as headers.&lt;/p&gt;
&lt;p&gt;O segundo é usado para retornar dados para quem o chamou.&lt;/p&gt;
&lt;p&gt;Nesse caso com:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusCode &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;200&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;nós definimos a propriedade statusCode como 200, para indicar uma resposta bem sucedida.&lt;/p&gt;
&lt;p&gt;Nós definimos a header de Content-Type (tipo de conteúdo):&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;setHeader&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Content-Type&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;text/plain&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e nós fechamos a resposta, adicionando o conteúdo como um argumento do &lt;code class=&quot;language-text&quot;&gt;end()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;end&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hello World\n&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Frameworks e ferramentas para Node.js&lt;/h2&gt;
&lt;p&gt;Node.js é uma plataforma de baixo nível. Para facilitar e inspirar os desenvolvedores, milhares de bibliotecas são construidas sob o Node.js pela comunidade.&lt;/p&gt;
&lt;p&gt;Muitas delas se estabaleceram como opções populares ao decorrer do tempo. Aqui está uma pequena lista com algumas que valem a pena aprender:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;a href=&quot;https://adonisjs.com/&quot;&gt;&lt;strong&gt;AdonisJs&lt;/strong&gt;&lt;/a&gt;: Um framework full-stack altamente focado na ergonomia, estabilidade e confiança do desenvolvedor. Adonis é um dos frameworks web Node.js mais rápidos.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://expressjs.com/&quot;&gt;&lt;strong&gt;Express&lt;/strong&gt;&lt;/a&gt;: Provê os meios de se criar servidores web de uma forma muito simples porém poderosa. Têm uma pegada minimalista, não opinada, focada nas funções essenciais de um servidor, que são a chave do sucesso.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://fastify.io/&quot;&gt;&lt;strong&gt;Fastify&lt;/strong&gt;&lt;/a&gt;: Um framework altamente focado em prover a melhor experiência ao desenvolvedor, com o mínimo de gargalos na performance e uma podesora arquitetura de extensões (plugins). Fastify é um dos mais rápidos frameworks Node.js.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.gatsbyjs.com/&quot;&gt;&lt;strong&gt;Gatsby&lt;/strong&gt;&lt;/a&gt;: Um gerador de sites estáticos baseado em &lt;a href=&quot;https://reactjs.org/&quot;&gt;React&lt;/a&gt;, gerido com &lt;a href=&quot;https://graphql.org/&quot;&gt;GraphQL&lt;/a&gt; e com um ecossistema de plugins e templates iniciais requíssimo.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://hapijs.com&quot;&gt;&lt;strong&gt;hapi&lt;/strong&gt;&lt;/a&gt;: Um rico framework para construção de aplicações e serviços que habilitam desenvolvedores a focar na escrita das lógicas de aplicação reutilizáveis em vez de perder tempo montando a infraestrutura.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;http://koajs.com/&quot;&gt;&lt;strong&gt;koa&lt;/strong&gt;&lt;/a&gt;: É mantido pelo time por trás do Express, pretende ser ainda menor e simples, construido sob muitos anos de conhecimento. O novo projeto nasceu da necessidade de criar mudanças incompatíveis sem romper com a comunidade existente.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://loopback.io/&quot;&gt;&lt;strong&gt;Loopback.io&lt;/strong&gt;&lt;/a&gt;: Faz com que seja fácil construir aplicações modernas que requerem integrações complexas.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://meteor.com&quot;&gt;&lt;strong&gt;Meteor&lt;/strong&gt;&lt;/a&gt;: Um framework full-stack incrivelmente poderoso, permite que você crie aplições Javascript com uma abordagem isomórfica, compartilhando código entre cliente e servidor. É uma ferramenta generalista que tenta fornecer tudo, que agora integra com bibliotecas frontend como &lt;a href=&quot;https://reactjs.org/&quot;&gt;React&lt;/a&gt;, &lt;a href=&quot;https://vuejs.org/&quot;&gt;Vue&lt;/a&gt;, e &lt;a href=&quot;https://angular.io&quot;&gt;Angular&lt;/a&gt;. Também pode ser utilizado para criar aplicativos mobile.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://github.com/zeit/micro&quot;&gt;&lt;strong&gt;Micro&lt;/strong&gt;&lt;/a&gt;: Provê um servidor enxuto para criação de microserviços HTTP assíncronos.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://nestjs.com/&quot;&gt;&lt;strong&gt;NestJS&lt;/strong&gt;&lt;/a&gt;: Um framework Node.js progressivo baseado em Typescript para construção de aplicação de nível empresarial eficientes, confiáveis e escaláveis.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://nextjs.org/&quot;&gt;&lt;strong&gt;Next.js&lt;/strong&gt;&lt;/a&gt;: Framework &lt;a href=&quot;https://reactjs.org&quot;&gt;React&lt;/a&gt; que fornce a melhor experiência de desenvolvimento, com todos os recursos que você precisa para produção: renderização híbrida entre servidor (SSR) e estáticos, suporte ao TypeScript, bundle otimizado, rotas pre-fetching, e mais.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://nx.dev/&quot;&gt;&lt;strong&gt;Nx&lt;/strong&gt;&lt;/a&gt;: Um conjunto de ferramentas para desenvolvimento full-stack em monorepo, utilizando NestJS, &lt;a href=&quot;https://reactjs.org/&quot;&gt;React&lt;/a&gt;, &lt;a href=&quot;https://angular.io&quot;&gt;Angular&lt;/a&gt;, e mais! Nx ajuda a escalar seu desenvolvimento de um time construindo uma aplicação para múltiplos times colaborando em múltiplas aplicações!&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://sapper.svelte.dev/&quot;&gt;&lt;strong&gt;Sapper&lt;/strong&gt;&lt;/a&gt;: Sapper é um framework para construção de aplicações web de todos os tamanhos, com uma bela experiências de desenvolvimento e roteamento flexível baseado em filesystems. Oferece SSR e muito mais!&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://socket.io/&quot;&gt;&lt;strong&gt;Socket.io&lt;/strong&gt;&lt;/a&gt;: Um motor de comunição em tempo real para construir aplicações em rede.&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://strapi.io/&quot;&gt;&lt;strong&gt;Strapi&lt;/strong&gt;&lt;/a&gt;: Strapi é um CMS flexível, open-source e independente, que fornece aos desenvolvedores a liberdade de escolher seus frameworks e ferramentas favoritos, enquanto também permite que editores administrem e distribuam seus conteúdos de maneira fácil. Por fazer o painel administrativo uma API extensível através de um sistema de plugins, o Strapi permite que as maiores empresas do mundo acelerem a entrega de conteúdo enquanto constroem belas experiências digitais.&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;Uma breve história do Node.js&lt;/h2&gt;
&lt;p&gt;Acredite ou não, Node.js só tem 11 anos de idade.&lt;/p&gt;
&lt;p&gt;Em comparação, &lt;a href=&quot;https://en.wikipedia.org/wiki/JavaScript#Beginnings_at_Netscape&quot;&gt;o JavaScript tem 24 anos&lt;/a&gt; e &lt;a href=&quot;https://howoldistheinter.net/&quot;&gt;a Web tem 31 anos&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Na tecnologia, 11 anos não é um tempo muito longo, mas o Node.js parece ter existido sempre.&lt;/p&gt;
&lt;p&gt;Eu tive o prazer de trabalhar com Node.js desde os primórdios quando ele só tinha 2 anos, e apesar das informações limitadas pela web, você já podia sentir que o crescimento seria enorme.&lt;/p&gt;
&lt;p&gt;Nesse post, vamos dissecar a história do Node.js, para colocar as coisas em perspectiva.&lt;/p&gt;
&lt;h2&gt;Um pouco de história&lt;/h2&gt;
&lt;p&gt;JavaScript é uma linguagem de programação que foi criada no Netscape como uma ferramente de scripts para manipulação de páginas web dentro do browser &lt;a href=&quot;https://en.wikipedia.org/wiki/Netscape_Navigator&quot;&gt;Netscape Navigator&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Parte do modelo de negócios da Netscape era vender servidores web, o que incluia um ambiente chamado &lt;em&gt;Netscape LiveWire&lt;/em&gt;, que podia criar páginas dinâmicas usando JavaScript no server-side.
Infelizmente, o &lt;em&gt;Netscape LiveWire&lt;/em&gt; não obteve muito sucesso e JavaScript server-side não era popular até recentemente, com a introdução do Node.js&lt;/p&gt;
&lt;p&gt;Um fator chave que levou o Node.js ao topo foi o timing. Apenas alguns poucos anos antes, Javascript começou a ser mais considerado como uma linguagem séria, graças às aplicações “Web 2.0” (como Flickr, Gmail, etc.) que mostraram ao mundo como poderia ser uma experiência moderna na web.&lt;/p&gt;
&lt;p&gt;Motores JavaScript (engines) também se tornaram consideravelmente melhores com a competição entre vários browsers para fornecer aos usuários a melhor performance. Times de desenvolvimento por trás dos maiores browsers trabalharam duro para oferecer melhor suporte para o JavaScript e encontrar meios que o fizesse rodar mais rápido. A engine que roda por baixo dos panos do Node.js, V8 (também conhecida como Chrome V8 por ser a engine Javascript open-source do Projeto Chromium), melhorou significamente devido a esta competição.&lt;/p&gt;
&lt;p&gt;Aconteceu de o Node.js ser criado no lugar certo e na hora certa, mas sorte não é a única razão do porquê ser tão popular hoje. Ele introduz várias abordagens e estratégias inovadoras para o desenvolvimento sever-side com JavaScript que já ajudaram diversos desenvolvedores.&lt;/p&gt;
&lt;h2&gt;2009&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;Nasce o Node.js&lt;/li&gt;
&lt;li&gt;A primeira forma do &lt;a href=&quot;https://www.npmjs.com/&quot;&gt;npm&lt;/a&gt; é criada&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2010&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;Nasce o &lt;a href=&quot;https://expressjs.com/&quot;&gt;Express&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;Nasce o &lt;a href=&quot;https://socket.io&quot;&gt;Socket.io&lt;/a&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2011&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;npm alcança a versão 1.0&lt;/li&gt;
&lt;li&gt;Grandes empresas começam a adotar Node.js: LinkedIn, Uber, etc.&lt;/li&gt;
&lt;li&gt;Nasce o &lt;a href=&quot;https://hapijs.com&quot;&gt;hapi&lt;/a&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2012&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;Adoção continua muito rápida&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2013&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;Primeira grande plataforma de blogs usando Node.js: &lt;a href=&quot;https://ghost.org/&quot;&gt;Ghost&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;Nasce o &lt;a href=&quot;https://koajs.com/&quot;&gt;Koa&lt;/a&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2014&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;O Grande Fork: &lt;a href=&quot;https://iojs.org/&quot;&gt;io.js&lt;/a&gt; é o maior fork do Node.js, com o objetivo de introduzir suporte ao ES6 e crescer rapidamente.&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2015&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;Nasce a &lt;a href=&quot;https://foundation.nodejs.org/&quot;&gt;Node.js Foundation&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;IO.js é mergeado de volta ao Node.js&lt;/li&gt;
&lt;li&gt;npm introduz módulos privados&lt;/li&gt;
&lt;li&gt;Node.js 4 (versões 1, 2 e 3 nunca foram lançadas previamente)&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2016&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;O incidente de &lt;a href=&quot;https://blog.npmjs.org/post/141577284765/kik-left-pad-and-npm&quot;&gt;leftpad&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;Nasce o &lt;a href=&quot;https://yarnpkg.com/en/&quot;&gt;Yarn&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;Node.js 6&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2017&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;npm aumenta o foco em segurança&lt;/li&gt;
&lt;li&gt;Node.js 8&lt;/li&gt;
&lt;li&gt;HTTP/2&lt;/li&gt;
&lt;li&gt;V8 introduz o Node.js em sua suite de testes, fazendo do Node.js oficialmente um alvo da engine, em adição ao Chrome&lt;/li&gt;
&lt;li&gt;3 bilhões de downloads no npm toda semana&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2018&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;Node.js 10&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://nodejs.org/api/esm.html&quot;&gt;ES modules&lt;/a&gt;: suporte experimental ao .mjs&lt;/li&gt;
&lt;li&gt;Node.js 11&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2019&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;Node.js 12&lt;/li&gt;
&lt;li&gt;Node.js 13&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;2020&lt;/h2&gt;
&lt;ul&gt;
&lt;li&gt;Node.js 14&lt;/li&gt;
&lt;li&gt;Node.js 15&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;Como instalar o Node.js&lt;/h2&gt;
&lt;p&gt;Node.js pode ser instalado de diferentes formas. Esse post destaca as mais comuns e convenientes.&lt;/p&gt;
&lt;p&gt;Pacotes oficiais para todas as principais plataformas estão disponíveis em &lt;a href=&quot;https://nodejs.org/en/download/&quot;&gt;https://nodejs.org/en/download/&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Uma maneira muito conveniente de instalar o Node.js é através de um gerenciador de pacotes. Neste caso, cada sistema operacional tem sua abordagem mais adequada.&lt;/p&gt;
&lt;p&gt;No macOS, &lt;a href=&quot;https://brew.sh/&quot;&gt;Homebrew&lt;/a&gt; é a alternativa oficial, e - uma vez instalado - permite que a instalação do Node.js seja feita facilmente, rodando esse comando na CLI:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;brew &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; node&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Outros gerenciadores de pacote para Linux e Windows estão listados em &lt;a href=&quot;https://nodejs.org/en/download/package-manager/&quot;&gt;https://nodejs.org/en/download/package-manager/&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;nvm&lt;/code&gt; é um maneira muito popular de rodar Node.js. Ele permite que você troque facilmente entre versões, e instale novas versões para testar e troque de volta caso algo pare de funcionar, por exemplo.&lt;/p&gt;
&lt;p&gt;Também é muito útil para testar seu código com versões antigas do Node.js&lt;/p&gt;
&lt;p&gt;Veja &lt;a href=&quot;https://github.com/creationix/nvm&quot;&gt;https://github.com/creationix/nvm&lt;/a&gt; para mais informações sobre essa opção.&lt;/p&gt;
&lt;p&gt;Minha sugestão é utilizar o instalador oficial se você só estiver começando e não utiliza o Homebrew, caso contrário, o Homebew é a minha solução favorita.&lt;/p&gt;
&lt;p&gt;Em todo caso, quando o Node.js é instalado você terá acesso ao comando executável &lt;code class=&quot;language-text&quot;&gt;node&lt;/code&gt; na linha de comando.&lt;/p&gt;
&lt;h2&gt;O que devo saber de Javascript para usar o Node.JS?&lt;/h2&gt;
&lt;p&gt;Como um iniciante, é difícil chegar no ponto onde você é confiante o suficiente nas suas habilidades de programação.&lt;/p&gt;
&lt;p&gt;Enquanto aprende a programar, você também pode ficar confuso sobre onde o JavaScript termina, e onde o Node.js começa, e vice versa.&lt;/p&gt;
&lt;p&gt;Eu recomendo que você tenha um bom domínio dos principais conceitos do JavaScript antes de mergulhar no Node.js:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Estrutura Léxica&lt;/li&gt;
&lt;li&gt;Expressões&lt;/li&gt;
&lt;li&gt;Tipos&lt;/li&gt;
&lt;li&gt;Variáveis&lt;/li&gt;
&lt;li&gt;Funções&lt;/li&gt;
&lt;li&gt;this&lt;/li&gt;
&lt;li&gt;Arrow Functions&lt;/li&gt;
&lt;li&gt;Loops&lt;/li&gt;
&lt;li&gt;Escopos&lt;/li&gt;
&lt;li&gt;Arrays&lt;/li&gt;
&lt;li&gt;Template Literals&lt;/li&gt;
&lt;li&gt;Semicolons (;)&lt;/li&gt;
&lt;li&gt;Strict Mode&lt;/li&gt;
&lt;li&gt;ECMAScript 6, 2016, 2017&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Com esses conceitos em mente, você está no caminho certo para se tornar um desenvolvedor proficiente em JavaScript, tanto Browser como também Node.js.&lt;/p&gt;
&lt;p&gt;Os conceitos a seguir também são essenciais para entender programação assíncrona, que é uma parte fundamental do Node.js:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Programação Assíncrona e callbacks&lt;/li&gt;
&lt;li&gt;Timers&lt;/li&gt;
&lt;li&gt;Promises&lt;/li&gt;
&lt;li&gt;Async e Await&lt;/li&gt;
&lt;li&gt;Closures&lt;/li&gt;
&lt;li&gt;Event Loop&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;Qual a diferença do Node.JS e do Browser?&lt;/h2&gt;
&lt;p&gt;Ambos browser e Node.js utilizam JavaScript como sua linguagem de programação.&lt;/p&gt;
&lt;p&gt;Construir aplicações que rodem no browser é uma coisa completamente diferente de construir aplicações Node.js&lt;/p&gt;
&lt;p&gt;Apesar do fato que é sempre JavaScript, há fatores chave que tornam a experiência radicalmente diferente.&lt;/p&gt;
&lt;p&gt;Da perspectiva de um desenvolvedor frontend que usa JavaScript extensivamente, aplicações Node.js trazem consigo uma enorme vantagem: o conforto de programar tudo - o frontend e o backend - em uma única linguagem.&lt;/p&gt;
&lt;p&gt;Você tem uma grande oportunidade porque nós sabemos quão difícil é para aprender, completa e profundamente, uma nova linguagem de programação, e por usar a mesma linguagem para fazer todo o trabalho na web - tanto no servidor quanto no cliente, você está em uma posição única de vantagem.&lt;/p&gt;
&lt;p&gt;O que muda é o ecossistema.&lt;/p&gt;
&lt;p&gt;No browser, na maioria do tempo o que você está fazendo é interagindo com o DOM, ou outras APIs Web como Cookies. Isso não existe no Node.js, é claro. Você não tem o &lt;code class=&quot;language-text&quot;&gt;document&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;window&lt;/code&gt; e todos os outros objetos que são providos pelo browser.&lt;/p&gt;
&lt;p&gt;E no browser, nós não temos as APIs legais que o Node.js provê com seus módulos, como a funcionalidade de acesso ao filesystem.&lt;/p&gt;
&lt;p&gt;Outra grande diferença é que no Node.js você controla seu ambiente. A não ser que você esteja criando uma aplicação open source que qualquer um pode hospedar em qualquer lugar, você sabe em qual versão do Node.js a aplicação vai rodar. Comparado ao ambiente do browser, onde você não tem o luxo de escolher qual browser seu visitante vai utilizar, isso é muito conveniente.&lt;/p&gt;
&lt;p&gt;Isso significa que você pode escrever códigos com os modernos ES6-7-8-9, se atentando ao suporte da sua versão do Node.js.&lt;/p&gt;
&lt;p&gt;Visto que o JavaScript se move muito rápido, mas os browsers podem ser um pouco lentos para atualizarem, as vezes na web, você está preso em versões velhas do JavaScript / ECMAScript.&lt;/p&gt;
&lt;p&gt;Você pode utilizar o Babel para transformar seu código em um formato compátivel com ES5 antes de enviar para o browser, mas no Node.js, você não precisa disso.&lt;/p&gt;
&lt;p&gt;Outra diferença é que o Node.js utiliza o sistema de módulos CommonJS, enquanto que nos browsers ainda estamos vendo o inicio da implementação do padrão ES Modules.&lt;/p&gt;
&lt;p&gt;Na prática, isso signifca que por enquanto você utiliza &lt;code class=&quot;language-text&quot;&gt;require()&lt;/code&gt; no Node.js e &lt;code class=&quot;language-text&quot;&gt;import&lt;/code&gt; no browser.&lt;/p&gt;
&lt;h2&gt;O motor V8 do JAvascript&lt;/h2&gt;
&lt;p&gt;V8 é o nome da engine JavaScript que roda no Google Chrome. É a coisa que pega nosso JavaScript e o executa enquanto navegamos com o Chrome.&lt;/p&gt;
&lt;p&gt;V8 provê o ambiente de execução em que o JavaScript executa. O DOM, e outras APIs web são fornecidas pelo browser.&lt;/p&gt;
&lt;p&gt;O legal é que a engine JavaScript é independente do browser que ela está hospedada. Essa funcionalidade chave possibilitou a ascensão do Node.js. A V8 foi escolhida como engine por trás do Node.js em 2009, e com a explosão de popularidade do Node.js, a V8 se tornou a engine que agora possibilita uma quantidade incrível de código sever-side escrito em JavaScript.&lt;/p&gt;
&lt;p&gt;O ecossistema Node.js é enorme e isso graças à V8 que também possibilitou aplicações desktop, com projetos como o Electron.&lt;/p&gt;
&lt;h2&gt;Outras engines JS&lt;/h2&gt;
&lt;p&gt;Outros browsers têm suas própias engines:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Firefox tem a &lt;a href=&quot;https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey&quot;&gt;&lt;strong&gt;SpiderMonkey&lt;/strong&gt;&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;Safari tem a &lt;a href=&quot;https://developer.apple.com/documentation/javascriptcore&quot;&gt;&lt;strong&gt;JavaScriptCore&lt;/strong&gt;&lt;/a&gt; (também chamada de Nitro)&lt;/li&gt;
&lt;li&gt;Edge foi originalmente basedo na &lt;a href=&quot;https://github.com/Microsoft/ChakraCore&quot;&gt;&lt;strong&gt;Chakra&lt;/strong&gt;&lt;/a&gt; mas recentemente &lt;a href=&quot;https://support.microsoft.com/en-us/help/4501095/download-the-new-microsoft-edge-based-on-chromium&quot;&gt;foi refeito utilizando Chromium&lt;/a&gt; e a V8.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;e existem muitas outras também.&lt;/p&gt;
&lt;p&gt;Todas essas engines implementam o &lt;a href=&quot;https://www.ecma-international.org/publications/standards/Ecma-262.htm&quot;&gt;padrão ECMA ES-262&lt;/a&gt;, também chamado de ECMAScript, o padrão utilizado pelo JavaSript.&lt;/p&gt;
&lt;h2&gt;A busca por performance&lt;/h2&gt;
&lt;p&gt;V8 foi escrita em C++, e é continuamente melhorada. É portável e roda no Mac, Windows, Linux e diversos outros sistemas.&lt;/p&gt;
&lt;p&gt;Nessa introdução à V8, vamos ignorar os detalhes de implementação: eles podem ser encontrados em sites mais apropriados (por exemplo, o &lt;a href=&quot;https://v8.dev/&quot;&gt;site oficial da V8&lt;/a&gt;), e eles mudam com o passar do tempo, frequentemente.&lt;/p&gt;
&lt;p&gt;V8 está sempre evoluindo, assim como as outras engines JavaScript ao seu redor, para agilizar a Web e o ecossistema Node.js.&lt;/p&gt;
&lt;p&gt;Na web, há uma corrida por performance que vem sendo travada por anos, e nós (como usuários e desenvolvedores) nos beneficiamos muito por essa competição, porque nós possuímos máquinas mais rápidas e otimizadas ano a ano.&lt;/p&gt;
&lt;h2&gt;Compilação&lt;/h2&gt;
&lt;p&gt;JavaScript é geralmente considerado como uma linguagem interpretada, mas engines modernas de JavaScript não o interpretam apenas, elas o compilam.&lt;/p&gt;
&lt;p&gt;Isso vem acontecendo desde 2009, quando o compilador JavaScript SpiderMonkey foi adicionado no Firefox 3.5, e todo mundo seguiu essa ideia.&lt;/p&gt;
&lt;p&gt;JavaScript é internamente compilado pela v8 com &lt;strong&gt;compilação just-in-time&lt;/strong&gt; (JIT) para acelerar a execução.&lt;/p&gt;
&lt;p&gt;Isso pode parecer contra-intuitivo, mas desde a introdução do Google Maps em 2004, o JavaScript evoluiu de uma linguagem que geralmente executava poucas dúzias de linhas de código, para aplicações completas com centenas de milhares de linhas de código executando no browser.&lt;/p&gt;
&lt;p&gt;Nossas aplicações agora podem rodar por horas dentro do browser, em vez de uma simples validação de regras de formulários ou scripts banais.&lt;/p&gt;
&lt;p&gt;Nesse &lt;em&gt;novo mundo&lt;/em&gt;, compilar JavaScript faz total sentido porque, embora possa demorar um pouco mais para termos o código JavaScript &lt;em&gt;pronto&lt;/em&gt;, uma vez concluída a compilação temos muito mais desempenho do que código puramente interpretado.&lt;/p&gt;
&lt;h2&gt;Rode scripts do Node a partir da linha de comando do Linux&lt;/h2&gt;
&lt;p&gt;A maneira mais usual de rodar um programa Node.js é executando o comando &lt;code class=&quot;language-text&quot;&gt;node&lt;/code&gt; disponível globalmente (uma vez instalado o Node.js) e passando o nome do arquivo desejado.&lt;/p&gt;
&lt;p&gt;Considerando que o arquivo principal da sua aplicação Node.js se chame &lt;code class=&quot;language-text&quot;&gt;app.js&lt;/code&gt;, você pode executá-lo digitando:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;node app.js&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Enquanto executa o comando, tenha certeza de estar no mesmo diretório que contêm o arquivo &lt;code class=&quot;language-text&quot;&gt;app.js&lt;/code&gt;.&lt;/p&gt;
&lt;h2&gt;Como sair de um programa Node.JS&lt;/h2&gt;
&lt;p&gt;Há várias maneiras de finalizar uma aplicação Node.js.&lt;/p&gt;
&lt;p&gt;Com o programa rodando no console, você pode fechá-lo com &lt;code class=&quot;language-text&quot;&gt;ctrl-C&lt;/code&gt;, mas o que queremos discutir aqui é a maneira programática de fazer isso.&lt;/p&gt;
&lt;p&gt;Vamos começar com a maneira mais drástica, e note porque é melhor você &lt;em&gt;não&lt;/em&gt; utilizá-la:&lt;/p&gt;
&lt;p&gt;O módulo nativo &lt;code class=&quot;language-text&quot;&gt;process&lt;/code&gt; provê um método prático que permite a você, programaticamente, sair de um programa Node.js: &lt;code class=&quot;language-text&quot;&gt;process.exit()&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Quando o Node.js executa essa linha, o processo é forçado a terminar imediatamente.&lt;/p&gt;
&lt;p&gt;Isso significa que qualquer callback pendente, qualquer request de rede sendo enviada, qualquer acesso ao filesystem, ou processos de escrita no &lt;code class=&quot;language-text&quot;&gt;stdout&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;stderr&lt;/code&gt; - tudo será finalizado de imediato &lt;em&gt;desgraciadamente&lt;/em&gt;.&lt;/p&gt;
&lt;p&gt;Se isso está bem para você, basta passar um inteiro que sinalize o código de saída para o sistema operacional:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;exit&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Por padrão, o código de saída é &lt;code class=&quot;language-text&quot;&gt;0&lt;/code&gt;, que significa sucesso. Códigos de saída diferentes tem significados diferentes, que você pode querer utilizar no seu sistema para se comunicar com outros programas.&lt;/p&gt;
&lt;p&gt;Você pode ler mais sobre os códigos de saída em &lt;a href=&quot;https://nodejs.org/api/process.html#process_exit_codes&quot;&gt;https://nodejs.org/api/process.html#process_exit_codes&lt;/a&gt;;&lt;/p&gt;
&lt;p&gt;Você também pode definir a propriedade &lt;code class=&quot;language-text&quot;&gt;process.exitCode&lt;/code&gt; como:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;exitCode &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e quando o programa for encerrado posteriormente, o Node.js retornará esse código de saída.&lt;/p&gt;
&lt;p&gt;Um programa irá sair graciosamente quando todos os processos estiverem completos.&lt;/p&gt;
&lt;p&gt;Muitas vezes nós iniciamos servidores Node.js, como esse servidor HTTP:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; express &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;express&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; app &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;express&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

app&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;get&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;send&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hi!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

app&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;listen&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;3000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Server ready&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Esse programa nunca terá um fim. Se você chamar &lt;code class=&quot;language-text&quot;&gt;process.exit()&lt;/code&gt;, qualquer requisição corrente/pendente será abortada. Isso &lt;em&gt;não é legal&lt;/em&gt;.&lt;/p&gt;
&lt;p&gt;Nesse caso, você precisa enviar ao comando um sinal de SIGTERM, e lidar com o processo desse sinal:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Nota: &lt;code class=&quot;language-text&quot;&gt;process&lt;/code&gt; não requer importação, está disponível automaticamente.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; express &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;express&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; app &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;express&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

app&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;get&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;send&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hi!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; server &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; app&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;listen&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;3000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Server ready&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;SIGTERM&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  server&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;close&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Process terminated&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;blockquote&gt;
&lt;p&gt;O que são sinais? Sinais são um sistema de intercomunicação POSIX: uma notificação enviada para um processo com o objetivo de notificar que um evento ocorreu.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;SIGKILL&lt;/code&gt; é o sinal que diz ao processo para que finalize imediatamente, e agirá idealmente como o &lt;code class=&quot;language-text&quot;&gt;process.exit()&lt;/code&gt;.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;SIGTERM&lt;/code&gt; é o sinal que diz ao processo para que termine graciosamente. É o sinal que é enviado por generenciadores de processo como &lt;code class=&quot;language-text&quot;&gt;upstart&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;supervisord&lt;/code&gt; e muitos outros.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Você pode enviar esse sinal por dentro da aplicação, em outra função:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;kill&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;pid&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;SIGTERM&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;ou de outro programa Node.js em execução, ou qualquer outra aplicação rodando em seu sistema que saiba o PID do processo que você deseja fianlizar.&lt;/p&gt;
&lt;h2&gt;Como ler Variáveis de ambiente a partir do Node.js?&lt;/h2&gt;
&lt;p&gt;O módulo nativo &lt;code class=&quot;language-text&quot;&gt;process&lt;/code&gt; do Node.js fornece a propriedade &lt;code class=&quot;language-text&quot;&gt;env&lt;/code&gt; que armazena todas as variáveis de ambiente que foram definidas no momento de início da aplicação.&lt;/p&gt;
&lt;p&gt;Aqui vai um exemplo que acessa a variável de ambiente NODE_ENV, que é definida com o valor &lt;code class=&quot;language-text&quot;&gt;development&lt;/code&gt; por padrão.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Nota: &lt;code class=&quot;language-text&quot;&gt;process&lt;/code&gt; não requer importação, está disponível automaticamente.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;env&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token constant&quot;&gt;NODE_ENV&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &quot;development&quot;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Defini-lá para “production” antes do script executar contará ao Node.js que é um ambiente de produção.&lt;/p&gt;
&lt;p&gt;Da mesma forma, você pode acessar/definir qualquer variável de ambiente customizada.&lt;/p&gt;
&lt;h2&gt;Como usar o REPL no Node&lt;/h2&gt;
&lt;p&gt;Nós usamos o comando &lt;code class=&quot;language-text&quot;&gt;node&lt;/code&gt; para executar scripts Node.js:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;node script.js&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Se nós omitirmos o nome do arquivo, iniciaremos o modo REPL:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;node&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;blockquote&gt;
&lt;p&gt;Nota: REPL (Read Evaluate Print Loop) é um ambiente para linguagem de programação (basicamente uma aba de console) que lê instruções individuais do input do usuário e após a execução, retorna o resultado no console.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Se você tentar isso agora no seu terminal, isto é o que vai acontecer:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;❯ node
&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;o comando permanece em modo de espera (idle) e aguarda alguma entrada.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Dica: se você não tem certeza de como abrir seu terminal, pesquise por “How to open terminal on &amp;#x3C;seu SO&gt;“.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Para ser mais exato, o REPL está aguardando a entrada de código JavaScript.&lt;/p&gt;
&lt;p&gt;Vamos começar de forma simples:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;console&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-console line-numbers&quot;&gt;&lt;code class=&quot;language-console&quot;&gt;&amp;gt; console.log(&amp;#39;test&amp;#39;)
test
undefined
&amp;gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;O primeiro valor, &lt;code class=&quot;language-text&quot;&gt;test&lt;/code&gt;, é a saída que esperavamos do log do console, e depois tivemos um undefined, que é o retorno de rodar &lt;code class=&quot;language-text&quot;&gt;console.log()&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Agora podemos inserir uma nova entrada de JavaScript.&lt;/p&gt;
&lt;h2&gt;Use o tab para autocomplete&lt;/h2&gt;
&lt;p&gt;O legal do REPL é que ele é interativo.&lt;/p&gt;
&lt;p&gt;Conforme você escreve seu código, se você pressionar o tecla &lt;code class=&quot;language-text&quot;&gt;tab&lt;/code&gt; o REPL vai tentar completar o que foi escrito para combinar com variáveis previamente definidas.&lt;/p&gt;
&lt;h2&gt;Explorando objetos do JavaScript&lt;/h2&gt;
&lt;p&gt;Tente digitar o nome de uma classe do JavaScript, como &lt;code class=&quot;language-text&quot;&gt;Number&lt;/code&gt;, e adicione um ponto e pressione &lt;code class=&quot;language-text&quot;&gt;tab&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;O REPL vai listar todas as propriedades e métodos que você pode acessar naquela classe:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/2b60eb9487f93b672da38e391d2e5e56/4a421/tab.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 57.12979890310786%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;Pressionando tab as propriedades do objeto são reveladas&quot;
        title=&quot;Pressionando tab as propriedades do objeto são reveladas&quot;
        src=&quot;/static/2b60eb9487f93b672da38e391d2e5e56/799d3/tab.png&quot;
        srcset=&quot;/static/2b60eb9487f93b672da38e391d2e5e56/00d96/tab.png 148w,
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/static/2b60eb9487f93b672da38e391d2e5e56/799d3/tab.png 590w,
/static/2b60eb9487f93b672da38e391d2e5e56/2a3d6/tab.png 885w,
/static/2b60eb9487f93b672da38e391d2e5e56/4a421/tab.png 1094w&quot;
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        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;h2&gt;Explore objetos globais&lt;/h2&gt;
&lt;p&gt;Você pode inspecionar os objetos globais que você tem acesso digitando &lt;code class=&quot;language-text&quot;&gt;global.&lt;/code&gt; e pressionando &lt;code class=&quot;language-text&quot;&gt;tab&lt;/code&gt;:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/c2bef52ca393ecb33846c54af34927a1/4a421/globals.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
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        title=&quot;Globals&quot;
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    &lt;/span&gt;&lt;/p&gt;
&lt;h2&gt;A variável especial _&lt;/h2&gt;
&lt;p&gt;Se depois de um código você digitar &lt;code class=&quot;language-text&quot;&gt;_&lt;/code&gt;, isso fará com que seja exibido o resultado da última operação.&lt;/p&gt;
&lt;h2&gt;Comandos com ponto (dot commands)&lt;/h2&gt;
&lt;p&gt;O REPL tem alguns comandos especiais, todos começando com um &lt;code class=&quot;language-text&quot;&gt;.&lt;/code&gt;. Eles são:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;.help&lt;/code&gt;: exibe a guia de ajuda dos dot commands.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;.editor&lt;/code&gt;: habilita o modo de editor, para escrever múltiplas linhas de código JavaScript com facilidade. Uma vez nesse modo, pressione ctrl-D para executar o código que foi escrito.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;.break&lt;/code&gt;: quando estiver inserindo um código com múltiplas linhas, utilizar o comando .break fará com que a entrada seja abortada. Mesma funcionalidade de pressionar ctrl-C.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;.clear&lt;/code&gt;: reinicia o contexto do REPL para um objeto vazio e cancela qualquer entrada corrente de múltiplas linhas.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;.load&lt;/code&gt;: carrega um arquivo JavaScript, relativo ao diretório atual.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;.save&lt;/code&gt;: salva todas suas entradas na sessão REPL em um arquivo (especifique um nome pro arquivo)&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;.exit&lt;/code&gt;: sai do repl (mesmo funcionamento de pressionar ctrl-C duas vezes)&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;O REPL sabe quando você está inserindo uma entrada com múltiplas linhas sem a necessidade de utilizar o &lt;code class=&quot;language-text&quot;&gt;.editor&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Por exemplo, se você começar a digitar uma iteração como essa:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;3&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;forEach&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;num&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e pressionar &lt;code class=&quot;language-text&quot;&gt;enter&lt;/code&gt;, o REPL irá para uma nova linha que começa com 3 pontos, indicando que você pode continuar a trabalhar naquele bloco.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token operator&quot;&gt;...&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;num&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token operator&quot;&gt;...&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Se você digitar &lt;code class=&quot;language-text&quot;&gt;.break&lt;/code&gt; no fim de uma linha, o modo múltiplas linhas irá parar e o código não será executado.&lt;/p&gt;
&lt;h2&gt;O Node.JS aceita argumentos a partir da linha de comando.&lt;/h2&gt;
&lt;p&gt;Você pode passar qualquer quantidade de argumentos quando está invocando uma aplicação Node.js, usando:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;node app.js&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Argumentos podem ser com chave e valor ou diretos (sem chave).&lt;/p&gt;
&lt;p&gt;Por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;node app.js joe&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;ou&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;node app.js &lt;span class=&quot;token assign-left variable&quot;&gt;name&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt;joe&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso muda em como você obterá os valores no código Node.js.&lt;/p&gt;
&lt;p&gt;A maneira de obtê-los é usando o objeto nativo &lt;code class=&quot;language-text&quot;&gt;process&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Ele expõe uma propriedade chamada &lt;code class=&quot;language-text&quot;&gt;argv&lt;/code&gt;, que é um array que contêm todos os argumentos passados na invocação.&lt;/p&gt;
&lt;p&gt;O primeiro elemento é o caminho absoluto do comando &lt;code class=&quot;language-text&quot;&gt;node&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;O segundo é o caminho absoluto do arquivo em execução.&lt;/p&gt;
&lt;p&gt;Todos os argumentos adicionais estão presentes da terceira posição em diante.&lt;/p&gt;
&lt;p&gt;Você pode iterar sobre todos os argumentos (incluindo o caminho do node e o do arquivo) usando um loop:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;argv&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;forEach&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;val&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; index&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;index&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;: &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;val&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;ou obter apenas os argumentos adicionais, criando um novo array que exclui os 2 primeiros parâmetros:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; args &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;argv&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;slice&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Se você tem um argumento direto (sem chave), como esse:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;node app.js joe&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;você pode acessá-lo usando&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; args &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;argv&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;slice&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
args&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Já nesse caso:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;node app.js &lt;span class=&quot;token assign-left variable&quot;&gt;name&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt;joe&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;args[0]&lt;/code&gt; é &lt;code class=&quot;language-text&quot;&gt;name=joe&lt;/code&gt;, e você precisa tratá-lo. A melhor maneira de fazer isso é usando a biblioteca &lt;a href=&quot;https://www.npmjs.com/package/minimist&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;minimist&lt;/code&gt;&lt;/a&gt;, que ajuda a lidar com argumentos:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; args &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;minimist&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;argv&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;slice&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
args&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;name&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;//joe&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Desta vez você você precisa usar dois traços antes do nome do argumento:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;node app.js --name&lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt;joe&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Output para a linha de comando usando Node.JS&lt;/h2&gt;
&lt;h2&gt;Saída (output) básico usando o módulo console&lt;/h2&gt;
&lt;p&gt;O Node.js provê o &lt;a href=&quot;https://nodejs.org/api/console.html&quot;&gt;módulo &lt;code class=&quot;language-text&quot;&gt;console&lt;/code&gt;&lt;/a&gt; que possui uma infinidade de maneiras muito úteis para interagir com a linha de comando.&lt;/p&gt;
&lt;p&gt;É basicamente o mesmo objeto &lt;code class=&quot;language-text&quot;&gt;console&lt;/code&gt; encontrado no browser.&lt;/p&gt;
&lt;p&gt;O método mais básico e mais usado é o &lt;code class=&quot;language-text&quot;&gt;console.log()&lt;/code&gt;, que imprime a string que você passar como parâmetro.&lt;/p&gt;
&lt;p&gt;Se você passar um objeto, ele irá renderizá-lo como uma string.&lt;/p&gt;
&lt;p&gt;Você pode passar múltiplas variáveis para o &lt;code class=&quot;language-text&quot;&gt;console.log&lt;/code&gt;, por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; x &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;x&apos;&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; y &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;y&apos;&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;x&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; y&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;o Node.js vai printar ambas.&lt;/p&gt;
&lt;p&gt;Nós também podemos formatar mensagens mais sofisticadas passando variáveis e um formato espeficador.&lt;/p&gt;
&lt;p&gt;Por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;My %s has %d years&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;cat&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;%s&lt;/code&gt; formata a variável como uma string&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;%d&lt;/code&gt; formata a variável como um número&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;%i&lt;/code&gt; formata a variável como um número, porém só a parte inteira&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;%o&lt;/code&gt; formata a variável como um objeto&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;%o&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; Number&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Limpando o console&lt;/h2&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;console.clear()&lt;/code&gt; limpa o console (o comportamento pode mudar dependendo do console utilizado).&lt;/p&gt;
&lt;h2&gt;Contando elementos&lt;/h2&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;console.count()&lt;/code&gt; é um método muito conveniente.&lt;/p&gt;
&lt;p&gt;Dado o código:&lt;/p&gt;
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&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; x &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; y &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; z &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;3&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;count&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;O valor de x é &apos;&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;+&lt;/span&gt; x &lt;span class=&quot;token operator&quot;&gt;+&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos; e foi validado .. quantas vezes?&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;count&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;O valor de x é &apos;&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;+&lt;/span&gt; x &lt;span class=&quot;token operator&quot;&gt;+&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos; e foi validado .. quantas vezes?&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;count&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;O valor de y é &apos;&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;+&lt;/span&gt; y &lt;span class=&quot;token operator&quot;&gt;+&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos; e foi validado .. quantas vezes?&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;O que acontece é que ele vai contar o número de vezes que uma string foi impressa, e imprime o total:&lt;/p&gt;
&lt;p&gt;Você pode contar maçãs e laranjas, por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; oranges &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;orange&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;orange&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; apples &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;just one apple&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;
oranges&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;forEach&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;fruit&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;count&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;fruit&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
apples&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;forEach&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;fruit&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;count&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;fruit&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Imprimindo a pilha de execução&lt;/h2&gt;
&lt;p&gt;Existem casos onde é útil imprimir a pilha de execução da função, talvez para responder a clássica pergunta &lt;em&gt;como você chegou nessa parte do código?&lt;/em&gt;&lt;/p&gt;
&lt;p&gt;Você pode isso fazer usando &lt;code class=&quot;language-text&quot;&gt;console.trace()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;function2&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;trace&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;function1&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;function2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;function1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso irá imprimir a pilha de execução. Isso é o que é impresso se tentarmos usá-lo no REPL do Node.js:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;Trace
    at function2 &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;repl:1:33&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    at function1 &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;repl:1:25&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    at repl:1:1
    at ContextifyScript.Script.runInThisContext &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;vm.js:44:33&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    at REPLServer.defaultEval &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;repl.js:239:29&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    at bound &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;domain.js:301:14&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    at REPLServer.runBound &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;as eval&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;domain.js:314:12&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    at REPLServer.onLine &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;repl.js:440:10&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    at emitOne &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;events.js:120:20&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    at REPLServer.emit &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;events.js:210:7&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Calculando o tempo gasto&lt;/h2&gt;
&lt;p&gt;Você pode calcular facilmente o tempo que uma função gasta para rodar, usando &lt;code class=&quot;language-text&quot;&gt;time()&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;timeEnd()&lt;/code&gt;&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;doSomething&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;test&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;measureDoingSomething&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;time&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;doSomething()&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;//faça algo, e calcule o tempo que isso levou&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;doSomething&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;timeEnd&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;doSomething()&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;measureDoingSomething&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;stdout e stderr&lt;/h2&gt;
&lt;p&gt;Como nós vimos o  console.log é ótimo para imprimir mensagens no console. Isso é o que chamamos de saída padrão, ou &lt;code class=&quot;language-text&quot;&gt;stdout&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;console.error&lt;/code&gt; imprime na stream &lt;code class=&quot;language-text&quot;&gt;stderr&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Isso não vai aparecer no console, mas vai aparecer no log de erro.&lt;/p&gt;
&lt;h2&gt;Colorindo o saída&lt;/h2&gt;
&lt;p&gt;Você pode colorir a saída do seu texto no console utilizando &lt;a href=&quot;https://gist.github.com/iamnewton/8754917&quot;&gt;escape sequences&lt;/a&gt;, que basicamente são um conjunto de caracteres que indentificam uma cor.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;\x1b[33m%s\x1b[0m&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;hi!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você pode testar isso no REPL no Node.js, onde será impresso &lt;code class=&quot;language-text&quot;&gt;hi!&lt;/code&gt; em amarelo.&lt;/p&gt;
&lt;p&gt;Entretanto, essa é uma abordagem mais baixo nível. O jeito mais simples de colorir saídas no console é utilizando uma biblioteca. &lt;a href=&quot;https://github.com/chalk/chalk&quot;&gt;Chalk&lt;/a&gt; é uma biblioteca que além de colorir, também ajuda com outras facilidades de estilização, como deixar textos em negrito, ítalico ou sublinhados.&lt;/p&gt;
&lt;p&gt;Instale com &lt;code class=&quot;language-text&quot;&gt;npm install chalk&lt;/code&gt;, e então use-o assim:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; chalk &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;chalk&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;chalk&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;yellow&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;hi!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Usando &lt;code class=&quot;language-text&quot;&gt;chalk.yellow&lt;/code&gt; é muito mais conveniente do que tentar lembrar o código de cor correto, e o código fica muito mais legível.&lt;/p&gt;
&lt;p&gt;Confira o link do projeto postado acima para mais exemplos de uso.&lt;/p&gt;
&lt;h2&gt;Crie uma barra de progresso&lt;/h2&gt;
&lt;p&gt;&lt;a href=&quot;https://www.npmjs.com/package/progress&quot;&gt;Progress&lt;/a&gt; é um pacote incrível para criar uma barra de progresso no console. Instale utilizando &lt;code class=&quot;language-text&quot;&gt;npm install progress&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Esse trecho cria uma barra de progresso com 10 passos, e a cada 100ms um passo é completado. Quando a barra é completada nós finalizamos o contador.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; ProgressBar &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;progress&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; bar &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;ProgressBar&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;:bar&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; total&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;10&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; timer &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;setInterval&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  bar&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;tick&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;bar&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;complete&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token function&quot;&gt;clearInterval&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;timer&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;100&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Aceite inputs do terminal no Node.js&lt;/h2&gt;
&lt;p&gt;Como criar um programa Node.js de CLI interativa?&lt;/p&gt;
&lt;p&gt;Desde a versão 7 o Node.js possui o &lt;a href=&quot;https://nodejs.org/api/readline.html&quot;&gt;módulo &lt;code class=&quot;language-text&quot;&gt;readline&lt;/code&gt;&lt;/a&gt; para fazer exatamente isso: obter entradas de uma stream de leitura, como a &lt;code class=&quot;language-text&quot;&gt;process.stdin&lt;/code&gt;, via terminal, durante a execução de um programa Node.js, uma linha por vez.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; readline &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;readline&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;createInterface&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  input&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;stdin&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  output&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;stdout
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

readline&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;question&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;What&apos;s your name?&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;name&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;Hi &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;name&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;!&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  readline&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;close&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Esse trecho de código pergunta o nome do usuário, e uma vez que o texto é inserido e o usuário pressiona enter, nós enviamos uma saudação.&lt;/p&gt;
&lt;p&gt;O método &lt;code class=&quot;language-text&quot;&gt;question()&lt;/code&gt; exibe o primeiro parâmetro (a pergunta) e aguarda pela entrada do usuário. A função de callback é invocada uma vez que o enter é pressionado.&lt;/p&gt;
&lt;p&gt;Nessa função de callback, nós fechamos a interface do readline.&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;readline&lt;/code&gt; oferece diversos outros métodos, e você pode conferir todos na documentação linkada acima.&lt;/p&gt;
&lt;p&gt;Se você precisa solicitar uma senha, o ideal é que os caracteres digitados sejam trocados pelo símbolo de &lt;code class=&quot;language-text&quot;&gt;*&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;A maneira mais simples de fazer isso é utilizar o &lt;a href=&quot;https://www.npmjs.com/package/readline-sync&quot;&gt;pacote &lt;code class=&quot;language-text&quot;&gt;readline-sync&lt;/code&gt;&lt;/a&gt;, que é muito similar em termos de API.&lt;/p&gt;
&lt;p&gt;Outra solução mais completa e abstrata é fornecida pelo &lt;a href=&quot;https://github.com/SBoudrias/Inquirer.js&quot;&gt;pacote Inquirer.js&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Instale-o utilizando &lt;code class=&quot;language-text&quot;&gt;npm install inquirer&lt;/code&gt;, e então você poderá replicar o código acima dessa forma:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; inquirer &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;inquirer&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;var&lt;/span&gt; questions &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    type&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;input&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    name&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;name&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    message&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;What&apos;s your name?&quot;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;

inquirer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;prompt&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;questions&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;answers&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;Hi &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;answers&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;name&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;!&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Inquirer.js permite com que você faça diversas coisas como perguntas de múltipla escolha, ter radio buttons, confirmações e muito mais.&lt;/p&gt;
&lt;p&gt;Vale a pena conhecer todas as alternativas, especialmente as nativas do Node.js, mas se você planeja levar a CLI para outro nível, Inquirer.js é ótima escolha.&lt;/p&gt;
&lt;h2&gt;Expondo uma funcionalidade em um arquivo do Node.js usando exports&lt;/h2&gt;
&lt;p&gt;O Node.js tem um sistema de módulos nativo.&lt;/p&gt;
&lt;p&gt;Um arquivo Node.js pode importar funcionalidades expostas por outros arquivos Node.js.&lt;/p&gt;
&lt;p&gt;Quando você quer importar algo você deve utilizar&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; library &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;./library&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;para importar a funcionalidade exposta no arquivo &lt;code class=&quot;language-text&quot;&gt;library.js&lt;/code&gt; que reside na pasta atual.&lt;/p&gt;
&lt;p&gt;Nesse arquivo, a funcionalidade deve ser exposta antes de poder ser importada por outros arquivos.&lt;/p&gt;
&lt;p&gt;Qualquer outra variável ou objeto definido no arquivo é privado por padrão e não exposto ao mundo exterior.&lt;/p&gt;
&lt;p&gt;Isso é permitido por meio da API &lt;code class=&quot;language-text&quot;&gt;module.exports&lt;/code&gt;, oferecida pelo &lt;a href=&quot;https://nodejs.org/api/modules.html&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;module&lt;/code&gt; system&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Quando você atribui um objeto ou uma função como uma nova propriedade do &lt;code class=&quot;language-text&quot;&gt;exports&lt;/code&gt;, isso se torna o que está sendo exposto, e como tal, pode ser importado em outras partes da sua aplicação, ou até em outras aplicações.&lt;/p&gt;
&lt;p&gt;Você pode fazer isso de 2 formas.&lt;/p&gt;
&lt;p&gt;A primeira é atribuir um objeto ao &lt;code class=&quot;language-text&quot;&gt;module.exports&lt;/code&gt;, que é um objeto provido nativamente pelo sistema de módulos, e ele fará com que o arquivo exporte &lt;em&gt;apenas aquele objeto&lt;/em&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; car &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  brand&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Ford&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  model&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Fiesta&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

module&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;exports &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; car

&lt;span class=&quot;token comment&quot;&gt;//..em outro arquivo&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; car &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;./car&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;A segunda é definir o objeto exportado como propriedade do &lt;code class=&quot;language-text&quot;&gt;exports&lt;/code&gt;. Essa abordagem permite que você exporte múltiplos objetos, funções ou dados:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; car &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  brand&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Ford&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  model&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Fiesta&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

exports&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;car &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; car&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;ou diretamente&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;exports&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;car &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  brand&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Ford&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  model&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Fiesta&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Em outro arquivo, você irá utilizá-lo referenciando a propriedade da sua importação:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; items &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;./items&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
items&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;car&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;ou&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; car &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;./items&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;car&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Qual a diferença entre &lt;code class=&quot;language-text&quot;&gt;module.exports&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;exports&lt;/code&gt;?&lt;/p&gt;
&lt;p&gt;O primeiro expõe o objeto para qual ele aponta.
O último expõe &lt;em&gt;as propriedades&lt;/em&gt; do objeto que ele aponta.&lt;/p&gt;
&lt;h2&gt;Uma introdução ao gerenciador de pacotes NPM&lt;/h2&gt;
&lt;h2&gt;Introdução ao npm&lt;/h2&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; é o gerenciador de pacotes padrão do Node.js.&lt;/p&gt;
&lt;p&gt;Em janeiro de 2017 mais de 350.000 pacotes foram listados no registro do npm, fazendo dele o maior repositório de código de uma única linguagem na Terra, e você pode ter certeza que existe um pacote para (quase!) tudo.&lt;/p&gt;
&lt;p&gt;Ele iniciou como um meio de fazer donwload e gerenciar dependências de pacotes Node.js, mas desde então ele se tornou uma ferramenta utilizada também no frontend.&lt;/p&gt;
&lt;p&gt;Há muitas coisas que o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; faz.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;&lt;a href=&quot;https://yarnpkg.com/en/&quot;&gt;&lt;strong&gt;Yarn&lt;/strong&gt;&lt;/a&gt; é uma alternativa ao npm. Não deixe de conferír.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;h2&gt;Downloads&lt;/h2&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; gerencia downloads de dependências do seu projeto.&lt;/p&gt;
&lt;h3&gt;Instalando todas dependências&lt;/h3&gt;
&lt;p&gt;Se o projeto tem um arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;, ao rodar&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;ele vai instalar tudo que o projeto precisa, na pasta &lt;code class=&quot;language-text&quot;&gt;node_modules&lt;/code&gt;, criando-a se não existir.&lt;/p&gt;
&lt;h3&gt;Instalando um único pacote&lt;/h3&gt;
&lt;p&gt;Você também pode instalar um pacote específico ao rodar&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;package-name&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Geralmente você verá mais flags adicionadas a esse comando:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;--save&lt;/code&gt; instala e adiciona uma entrada no campo &lt;em&gt;dependencies&lt;/em&gt; do arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;--save-dev&lt;/code&gt; instala e adiciona uma entrada no campo &lt;em&gt;devDependencies&lt;/em&gt; do arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;A principal diferença é que no devDependencies ficam as ferramentas de desenvolvimento, como uma biblioteca de testes, enquanto no &lt;code class=&quot;language-text&quot;&gt;dependencies&lt;/code&gt; ficam os pacotes necessários à aplicação em ambiente de produção.&lt;/p&gt;
&lt;h3&gt;Atualizando pacotes&lt;/h3&gt;
&lt;p&gt;Atualizar também é fácil, ao rodar&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;console&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-console line-numbers&quot;&gt;&lt;code class=&quot;language-console&quot;&gt;npm update&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; vai buscar em todos os pacotes por uma versão atualizada que satisfaça suas restrições de versionamento.&lt;/p&gt;
&lt;p&gt;Você também pode especificar um único pacote para atualizar:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;console&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-console line-numbers&quot;&gt;&lt;code class=&quot;language-console&quot;&gt;npm update &amp;lt;package-name&amp;gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Versionamento&lt;/h2&gt;
&lt;p&gt;Em adição aos downloads, o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; também gerencia o &lt;strong&gt;versionamento&lt;/strong&gt;, assim você pode especificar qualquer versão do pacote, ou uma versão maior ou menor do que você precisa.&lt;/p&gt;
&lt;p&gt;Muitas vezes você vai encontrar uma biblioteca que só é compatível com a versão atual de outra biblioteca.&lt;/p&gt;
&lt;p&gt;Ou um bug na versão mais atual da biblioteca, ainda não solucionado, causando um problema.&lt;/p&gt;
&lt;p&gt;Especificar explicitamente a versão da biblioteca também ajuda a manter todos na exata mesma versão do pacote, assim todos do time rodam a mesma versão até que o arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt; seja atualizado.&lt;/p&gt;
&lt;p&gt;Em todos os casos, versionar ajuda muito, e o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; segue o padrão semântico de versionamento chamado semver.&lt;/p&gt;
&lt;h2&gt;Executando tarefas&lt;/h2&gt;
&lt;p&gt;O arquivo package.json possui um campo chamado “scripts”, que é usado para especificar tarefas de linha de comando que podem ser rodadas usando&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;console&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-console line-numbers&quot;&gt;&lt;code class=&quot;language-console&quot;&gt;npm run &amp;lt;task-name&amp;gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;scripts&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;start-dev&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;node lib/server-development&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;start&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;node lib/server-production&quot;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;É muito comum usar esse recurso para rodar o Webpack:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;scripts&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;watch&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;webpack --watch --progress --colors --config webpack.conf.js&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;dev&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;webpack --progress --colors --config webpack.conf.js&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;prod&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;NODE_ENV=production webpack -p --config webpack.conf.js&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Então em vez de digitar esses comandos longos, que são muito fáceis de errar ou esquecer, você pode rodar&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;console&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-console line-numbers&quot;&gt;&lt;code class=&quot;language-console&quot;&gt;npm run watch
npm run dev
npm run prod&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Onde o Node instala os pacotes?&lt;/h2&gt;
&lt;p&gt;Quando você instala um pacote utilizando &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; você pode executar 2 tipos de instalação:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;local&lt;/li&gt;
&lt;li&gt;global&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Por padrão, quando você digita o comando &lt;code class=&quot;language-text&quot;&gt;npm install&lt;/code&gt;, como por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; lodash&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;o pacote será instalado na árvore de arquivos atual, em uma subpasta dentro da &lt;code class=&quot;language-text&quot;&gt;node_modules&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Quando isso ocorre, o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; também adiciona uma entrada do &lt;code class=&quot;language-text&quot;&gt;lodash&lt;/code&gt; na propriedade &lt;code class=&quot;language-text&quot;&gt;dependencies&lt;/code&gt; do arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt; da pasta atual.&lt;/p&gt;
&lt;p&gt;Para executar uma instalação global, basta utilizar a flag &lt;code class=&quot;language-text&quot;&gt;-g&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; -g lodash&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Quando isso ocorre, o npm não instalará na pasta local, em vez disso, ele utilizará uma localização global.&lt;/p&gt;
&lt;p&gt;Onde, exatamente?&lt;/p&gt;
&lt;p&gt;O comando &lt;code class=&quot;language-text&quot;&gt;npm root -g&lt;/code&gt; te dirá a localização exata na sua máquina.&lt;/p&gt;
&lt;p&gt;No macOS ou Linux, essa localização costuma ser &lt;code class=&quot;language-text&quot;&gt;/usr/local/lib/node_modules&lt;/code&gt;.
No Windows costuma ser &lt;code class=&quot;language-text&quot;&gt;C:\Users\YOU\AppData\Roaming\npm\node_modules&lt;/code&gt;&lt;/p&gt;
&lt;p&gt;Todavia, se você utiliza o &lt;code class=&quot;language-text&quot;&gt;nvm&lt;/code&gt; para gerenciar versões do Node.js, a localização pode ser diferente.&lt;/p&gt;
&lt;p&gt;Eu por exemplo utilizo &lt;code class=&quot;language-text&quot;&gt;nvm&lt;/code&gt; e a localização dos meus pacotes foi exibida como &lt;code class=&quot;language-text&quot;&gt;/Users/joe/.nvm/versions/node/v8.9.0/lib/node_modules&lt;/code&gt;.&lt;/p&gt;
&lt;h2&gt;Como usar ou executar um pacote instalado usando NPM?&lt;/h2&gt;
&lt;p&gt;Quando você instala um pacote usando &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; dentro da sua pasta &lt;code class=&quot;language-text&quot;&gt;node_modules&lt;/code&gt;, ou também globamente, como você o utiliza em seu código Node.js?&lt;/p&gt;
&lt;p&gt;Digamos que você instale a famosa biblioteca JavaScript de utilidades chamada &lt;code class=&quot;language-text&quot;&gt;lodash&lt;/code&gt;, usando&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; lodash&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso irá instalar o pacote na sua pasta &lt;code class=&quot;language-text&quot;&gt;node_modules&lt;/code&gt; local.&lt;/p&gt;
&lt;p&gt;Para utilizá-lo em seu código, você só precisa importá-lo no seu programa utilizando &lt;code class=&quot;language-text&quot;&gt;require&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; _ &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;lodash&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Mas e se o seu pacote for um executável?&lt;/p&gt;
&lt;p&gt;Nesse caso, ele para a pasta &lt;code class=&quot;language-text&quot;&gt;node_modules/.bin/&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Um jeito fácil de demonstrar isso é utilizando o &lt;a href=&quot;https://www.npmjs.com/package/cowsay&quot;&gt;cowsay&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;O pacote cowsay fornece um programa de linha de comando que faz com que uma vaca diga algo (e outros animais também 🦊).&lt;/p&gt;
&lt;p&gt;Quando você instala o pacote utilizando &lt;code class=&quot;language-text&quot;&gt;npm install cowsay&lt;/code&gt;, ele irá instalar a si mesmo e algumas poucas dependências na sua pasta node_modules local:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/b245c50f5080dae16a2525fae0ba2c91/6e914/node_modules-content.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 58.55758880516685%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;O conteúdo da pasta node_modules&quot;
        title=&quot;O conteúdo da pasta node_modules&quot;
        src=&quot;/static/b245c50f5080dae16a2525fae0ba2c91/799d3/node_modules-content.png&quot;
        srcset=&quot;/static/b245c50f5080dae16a2525fae0ba2c91/00d96/node_modules-content.png 148w,
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/static/b245c50f5080dae16a2525fae0ba2c91/799d3/node_modules-content.png 590w,
/static/b245c50f5080dae16a2525fae0ba2c91/2a3d6/node_modules-content.png 885w,
/static/b245c50f5080dae16a2525fae0ba2c91/6e914/node_modules-content.png 929w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Há uma pasta oculta chamada .bin, que contêm links simbólicos para os binários do cowsay:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/99830aefa055e247397de544ad7b7744/6e914/binary-files.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 38.213132400430574%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;Os arquivos binários&quot;
        title=&quot;Os arquivos binários&quot;
        src=&quot;/static/99830aefa055e247397de544ad7b7744/799d3/binary-files.png&quot;
        srcset=&quot;/static/99830aefa055e247397de544ad7b7744/00d96/binary-files.png 148w,
/static/99830aefa055e247397de544ad7b7744/0b23c/binary-files.png 295w,
/static/99830aefa055e247397de544ad7b7744/799d3/binary-files.png 590w,
/static/99830aefa055e247397de544ad7b7744/2a3d6/binary-files.png 885w,
/static/99830aefa055e247397de544ad7b7744/6e914/binary-files.png 929w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Como você executa isso?&lt;/p&gt;
&lt;p&gt;É claro que você pode digitar &lt;code class=&quot;language-text&quot;&gt;./node_modules/.bin/cowsay&lt;/code&gt; para executar, e vai funcionar, mas o npx, incluso nas versões recentes do npm (desde a 5.2), é uma opção muito melhor. Você só roda:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;npx cowsay&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e o npx vai encontrar a localização do pacote.&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/ad4f3d3a7464bb0f8a2845fe8e6588c2/6e914/cow-say.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 55.65123789020452%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;A vaca dizendo &amp;quot;take me out of here&amp;quot;&quot;
        title=&quot;A vaca dizendo &amp;quot;take me out of here&amp;quot;&quot;
        src=&quot;/static/ad4f3d3a7464bb0f8a2845fe8e6588c2/799d3/cow-say.png&quot;
        srcset=&quot;/static/ad4f3d3a7464bb0f8a2845fe8e6588c2/00d96/cow-say.png 148w,
/static/ad4f3d3a7464bb0f8a2845fe8e6588c2/0b23c/cow-say.png 295w,
/static/ad4f3d3a7464bb0f8a2845fe8e6588c2/799d3/cow-say.png 590w,
/static/ad4f3d3a7464bb0f8a2845fe8e6588c2/2a3d6/cow-say.png 885w,
/static/ad4f3d3a7464bb0f8a2845fe8e6588c2/6e914/cow-say.png 929w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;h2&gt;O Guia do package.json&lt;/h2&gt;
&lt;p&gt;Se você trabalha com JavaScript, ou já interagiu com um projeto JavaScript, Node.js ou um projeto frontend, você certamente conheceu o arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Pra que ele serve? O que você deveria saber sobre ele, e o quê de legal pode ser feito com ele?&lt;/p&gt;
&lt;p&gt;O &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt; é uma espécie de manifesto do seu projeto. Ele pode fazer uma variedade de coisas, completamente não relacionadas. É um repositório central de configurações para ferramentas, por exemplo. Também é onde o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; e o &lt;code class=&quot;language-text&quot;&gt;yarn&lt;/code&gt; armazenam os nomes e versões de todos os pacotes instalados.&lt;/p&gt;
&lt;h2&gt;The file structure&lt;/h2&gt;
&lt;p&gt;Aqui temos um exemplo de arquivo package.json:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Está vazio! Não há campos fixos obrigatórios do que pode ser colocado no arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;, de uma aplicação. A única exigência é que respeite o formato JSON, caso contrário programas que tentem acessar as propriedades programaticamente não terão sucesso.&lt;/p&gt;
&lt;p&gt;Se você está criando um pacote Node.js que precisa ser distribuido no &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; as coisas mudam radicalmente, e você necessita preencher algumas propriedades que vão ajudar outras pessoas a utilizar seu pacote. Vamos ver mais sobre isso em breve.&lt;/p&gt;
&lt;p&gt;Esse é outro package.json:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;name&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;test-project&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Ele define uma propriedade &lt;code class=&quot;language-text&quot;&gt;name&lt;/code&gt;, que diz o nome da aplicação, ou pacote, que está contido na mesma pasta em que o arquivo reside.&lt;/p&gt;
&lt;p&gt;Aqui temos outro exemplo muito mais complexo, que foi extraido de uma aplicação Vue.js:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;name&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;test-project&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;1.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;description&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;A Vue.js project&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;main&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;src/main.js&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;private&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;scripts&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;dev&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;webpack-dev-server --inline --progress --config build/webpack.dev.conf.js&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;start&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;npm run dev&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;unit&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;jest --config test/unit/jest.conf.js --coverage&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;test&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;npm run unit&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;lint&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;eslint --ext .js,.vue src test/unit&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;build&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;node build/build.js&quot;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;dependencies&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;vue&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.5.2&quot;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;devDependencies&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;autoprefixer&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^7.1.2&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-core&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^6.22.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-eslint&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^8.2.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-helper-vue-jsx-merge-props&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.0.3&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-jest&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^21.0.2&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-loader&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^7.1.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-plugin-dynamic-import-node&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.2.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-plugin-syntax-jsx&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^6.18.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-plugin-transform-es2015-modules-commonjs&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^6.26.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-plugin-transform-runtime&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^6.22.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-plugin-transform-vue-jsx&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^3.5.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-preset-env&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.3.2&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;babel-preset-stage-2&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^6.22.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;chalk&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.0.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;copy-webpack-plugin&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^4.0.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;css-loader&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^0.28.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;eslint&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^4.15.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;eslint-config-airbnb-base&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^11.3.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;eslint-friendly-formatter&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^3.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;eslint-import-resolver-webpack&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^0.8.3&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;eslint-loader&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.7.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;eslint-plugin-import&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.7.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;eslint-plugin-vue&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^4.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;extract-text-webpack-plugin&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^3.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;file-loader&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.1.4&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;friendly-errors-webpack-plugin&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.6.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;html-webpack-plugin&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.30.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;jest&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^22.0.4&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;jest-serializer-vue&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^0.3.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;node-notifier&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^5.1.2&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;optimize-css-assets-webpack-plugin&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^3.2.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;ora&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.2.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;portfinder&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.0.13&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;postcss-import&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^11.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;postcss-loader&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.0.8&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;postcss-url&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^7.2.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;rimraf&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.6.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;semver&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^5.3.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;shelljs&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^0.7.6&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;uglifyjs-webpack-plugin&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.1.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;url-loader&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^0.5.8&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;vue-jest&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.0.2&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;vue-loader&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^13.3.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;vue-style-loader&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^3.0.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;vue-template-compiler&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.5.2&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;webpack&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^3.6.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;webpack-bundle-analyzer&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.9.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;webpack-dev-server&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.9.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;webpack-merge&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^4.1.0&quot;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;engines&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;node&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;&gt;= 6.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;npm&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;&gt;= 3.0.0&quot;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;browserslist&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&quot;&gt; 1%&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;last 2 versions&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;not ie &amp;lt;= 8&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;há &lt;em&gt;muitas&lt;/em&gt; coisas rolando aqui:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;version&lt;/code&gt; indica a versão atual&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;name&lt;/code&gt; define o nome da aplicação&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;description&lt;/code&gt; é uma breve descrição da aplicação&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;main&lt;/code&gt; define o ponto de entrada da aplicação&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;private&lt;/code&gt; se definido como &lt;code class=&quot;language-text&quot;&gt;true&lt;/code&gt;, previne da aplicação ser publicada acidentalmente no &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;scripts&lt;/code&gt; define alguns scripts node que você pode rodar na linha de comando&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;dependencies&lt;/code&gt; define uma lista de pacotes &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; instalados como dependências&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;devDependencies&lt;/code&gt; define uma lista de pacotes &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; instalados como dependências de desenvolvimento&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;engines&lt;/code&gt; define em quais versões do Node.js essa aplicação funciona&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;browserslist&lt;/code&gt; é usado para definir quais browsers (e suas versões) você quer dar suporte&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Todas essas propriedades são usadas tanto pelo &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; quando outras ferramentas.&lt;/p&gt;
&lt;h2&gt;Separação de propriedades&lt;/h2&gt;
&lt;p&gt;Essa seção descreve as propriedades que você pode usar em detalhes. Nós nos referimos como “pacote” mas o mesmo se aplica à aplicações locais que você não utiliza como pacotes.&lt;/p&gt;
&lt;p&gt;A maioria dessas propriedades são usadas apenas no &lt;a href=&quot;https://www.npmjs.com/&quot;&gt;https://www.npmjs.com/&lt;/a&gt;, outras por scripts que interagem com seu código, como o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; ou outros.&lt;/p&gt;
&lt;h3&gt;name&lt;/h3&gt;
&lt;p&gt;Define o nome do pacote.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;name&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;test-project&quot;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;O nome deve ter menos de 214 caracteres, não pode ter espaços, apenas letras minúsculas, hífens (&lt;code class=&quot;language-text&quot;&gt;-&lt;/code&gt;) ou underlines (&lt;code class=&quot;language-text&quot;&gt;_&lt;/code&gt;).&lt;/p&gt;
&lt;p&gt;Isso ocorre porque quando um pacote é publicado no &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt;, ele ganha sua própria URL baseada nessa propriedade.&lt;/p&gt;
&lt;p&gt;Se você publicou esse pacote no GitHub, é uma boa definir essa propriedade com o nome do repositório no GitHub.&lt;/p&gt;
&lt;h3&gt;author&lt;/h3&gt;
&lt;p&gt;Lista o nome do autor do pacote&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;author&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;Joe &amp;lt;joe@whatever.com&gt; (https://whatever.com)&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Também pode ser usado com esse formato:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;author&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;name&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;Joe&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;email&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;joe@whatever.com&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;url&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://whatever.com&quot;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;contributors&lt;/h3&gt;
&lt;p&gt;Assim como o autor, o projeto pode ter muitos contribuidores. Essa propriedade é um array que os lista.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;contributors&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&quot;Joe &amp;lt;joe@whatever.com&gt; (https://whatever.com)&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Também pode ser usado com esse formato:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;contributors&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;name&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;Joe&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;email&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;joe@whatever.com&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;url&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://whatever.com&quot;&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;bugs&lt;/h3&gt;
&lt;p&gt;Link para o rastreador de issues do pacote, geralmente uma página de issues do GitHub&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;bugs&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://github.com/whatever/package/issues&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;homepage&lt;/h3&gt;
&lt;p&gt;Define a página inicial do site do pacote&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;homepage&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://whatever.com/package&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;version&lt;/h3&gt;
&lt;p&gt;Indica a versão atual do pacote.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;1.0.0&quot;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Essa propriedade segue o padrão de notação de versionamento semântico chamado &lt;em&gt;semver&lt;/em&gt;, o que significa que é sempre expresso com 3 números: &lt;code class=&quot;language-text&quot;&gt;x.x.x&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;O primeiro número é sempre a versão major, o segundo a versão minor e o terceiro a versão patch.&lt;/p&gt;
&lt;p&gt;Há um significado nesses números: uma versão que só corrige bugs é uma versão patch, uma versão que introduz mudanças compatíveis com versões anteriores é uma versão minor, uma versão major pode conter quebra de comportamentos com versões antigas.&lt;/p&gt;
&lt;h3&gt;license&lt;/h3&gt;
&lt;p&gt;Indica a licença do pacote.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;license&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;MIT&quot;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;keywords&lt;/h3&gt;
&lt;p&gt;Esse propriedade contêm um array de palavras chave que são associadas a o quê esse projeto faz.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;keywords&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&quot;email&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&quot;machine learning&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&quot;ai&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso ajuda pessoas a encontrarem seu pacote quando estiverem navegando por pacotes semelhantes, ou quando estiverem navegando no site &lt;a href=&quot;https://www.npmjs.com/&quot;&gt;https://www.npmjs.com/&lt;/a&gt;.&lt;/p&gt;
&lt;h3&gt;description&lt;/h3&gt;
&lt;p&gt;Essa propriedade contêm uma breve descrição do pacote&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;description&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;Um pacote para trabalhar com strings&quot;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso é útil especialmente se você decide publicar seu pacote no &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt;, assim as pessoas podem encontrar sobre o quê se trata aquele pacote.&lt;/p&gt;
&lt;h3&gt;repository&lt;/h3&gt;
&lt;p&gt;Essa propriedade especifica onde o repositório desse pacote está localizado.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;repository&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;github:whatever/testing&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Note o prefixo &lt;code class=&quot;language-text&quot;&gt;github&lt;/code&gt;. Também há outros serviços populares:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;repository&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;gitlab:whatever/testing&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;repository&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;bitbucket:whatever/testing&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você pode explicitar o sistema de controle de versionamento:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;repository&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;type&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;git&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;url&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://github.com/whatever/testing.git&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você pode usar diferentes tipos de controle de versionamento:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;repository&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;type&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;svn&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;url&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;...&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;main&lt;/h3&gt;
&lt;p&gt;Define o ponto de entrada do pacote.&lt;/p&gt;
&lt;p&gt;Quando você importa esse pacote em uma aplicação, é onde a aplicação vai procurar pelo &lt;em&gt;module exports&lt;/em&gt;.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;main&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;src/main.js&quot;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;private&lt;/h3&gt;
&lt;p&gt;Se definido como &lt;code class=&quot;language-text&quot;&gt;true&lt;/code&gt;, previne do pacote ser publicado acidentalmente no &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt;&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;private&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;scripts&lt;/h3&gt;
&lt;p&gt;Define um conjunto de scripts node que você pode executar&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;scripts&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;dev&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;webpack-dev-server --inline --progress --config build/webpack.dev.conf.js&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;start&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;npm run dev&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;unit&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;jest --config test/unit/jest.conf.js --coverage&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;test&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;npm run unit&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;lint&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;eslint --ext .js,.vue src test/unit&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;build&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;node build/build.js&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Esses scripts são aplicações de linha de comando. Você pode rodá-los usando &lt;code class=&quot;language-text&quot;&gt;npm run XXXX&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;yarn XXXX&lt;/code&gt;, sendo &lt;code class=&quot;language-text&quot;&gt;XXXX&lt;/code&gt; o nome do comando. Exemplo: &lt;code class=&quot;language-text&quot;&gt;npm run dev&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Você pode usar o nome que quiser para o comando, e os scripts podem fazer qualquer coisa.&lt;/p&gt;
&lt;h3&gt;dependencies&lt;/h3&gt;
&lt;p&gt;Define uma lista de pacotes &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; instalados como dependências.&lt;/p&gt;
&lt;p&gt;Quando você instala um pacote usando npm ou yarn:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;PACKAGENAME&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;yarn&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;add&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;PACKAGENAME&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;esse pacote é inserido automaticamente nessa lista.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;dependencies&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;vue&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.5.2&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;devDependencies&lt;/h3&gt;
&lt;p&gt;Define uma lista de pacotes &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; instalados como dependências de desenvolvimento.&lt;/p&gt;
&lt;p&gt;Eles se diferem dos pacotes no &lt;code class=&quot;language-text&quot;&gt;dependencies&lt;/code&gt; porque eles são instalados apenas em ambiente de desenvolvimento, não são necessários para rodar o código em produção.&lt;/p&gt;
&lt;p&gt;Quando você instala um pacote usando npm ou yarn:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; --save-dev &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;PACKAGENAME&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;yarn&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;add&lt;/span&gt; --dev &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;PACKAGENAME&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;esse pacote é inserido automaticamente nessa lista.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;devDependencies&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;autoprefixer&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^7.1.2&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;babel-core&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^6.22.1&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;engines&lt;/h3&gt;
&lt;p&gt;Define em quais versões do Node.js e outros comandos esse pacote opera&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;engines&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;node&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;&gt;= 6.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;npm&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;&gt;= 3.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;yarn&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^0.13.0&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;browserslist&lt;/h3&gt;
&lt;p&gt;É usado para definir quais browsers (e suas versões) você deseja dar suporte. É refenciado pelo Babel, Autoprefixer, e outras ferramentas, apenas para adicionar polyfills e fallbacks necessárias para o browser em questão.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token property&quot;&gt;&quot;browserslist&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&quot;&gt; 1%&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&quot;last 2 versions&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&quot;not ie &amp;lt;= 8&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Essa configuração implica que você quer dar suporte paras as 2 últimas versões major de todos os browsers com pelo menos 1% de uso (das estatísticas do &lt;a href=&quot;https://caniuse.com&quot;&gt;CanIUse.com&lt;/a&gt;), exceto IE8 ou anterior.&lt;/p&gt;
&lt;p&gt;(&lt;a href=&quot;https://www.npmjs.com/package/browserslist&quot;&gt;veja mais sobre&lt;/a&gt;)&lt;/p&gt;
&lt;h3&gt;Propriedades específicas de comandos&lt;/h3&gt;
&lt;p&gt;O arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt; também pode conter configurações específicas de comandos, como por exemplo Babel, ESLint, e mais.&lt;/p&gt;
&lt;p&gt;Cada um tem propriedades específicas, como &lt;code class=&quot;language-text&quot;&gt;eslintConfig&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;babel&lt;/code&gt; e outras. Você pode encontrar como utilizá-las em suas respectivas documentações.&lt;/p&gt;
&lt;h2&gt;Versões dos pacotes&lt;/h2&gt;
&lt;p&gt;Você viu nos exemplos acima números como esse: &lt;code class=&quot;language-text&quot;&gt;~3.0.0&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;^0.13.0&lt;/code&gt;. O que eles significam, e quais outros especificadores de versão você pode usar?&lt;/p&gt;
&lt;p&gt;O símbolo especifica quais atualizações seu pacote aceita, para aquela dependência.&lt;/p&gt;
&lt;p&gt;Dado que ao usar semver (versionamento semântico) todas versões têm 3 dígitos, o primeiro sendo a versão major, o segundo a versão minor e o terceiro a versão patch, você tem essas &lt;a href=&quot;https://nodejs.dev/learn/semantic-versioning-using-npm/&quot;&gt;regras&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Você pode combinar a maioria das versões em intervalos, como esse: &lt;code class=&quot;language-text&quot;&gt;1.0.0 || &amp;gt;=1.1.0 &amp;lt;1.2.0&lt;/code&gt;, para usar ou 1.0.0 ou uma versão maior ou igual que 1.1.0, mas menor que 1.2.0.&lt;/p&gt;
&lt;h2&gt;O arquivo package-lock.json&lt;/h2&gt;
&lt;p&gt;Na versão 5, o npm introduziu o arquivo &lt;code class=&quot;language-text&quot;&gt;package-lock.json&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;O que é isso? Você provavelmente conhece sobre o arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;, que é muito mais comum e está por aí a mais tempo.&lt;/p&gt;
&lt;p&gt;O objeto do arquivo é manter rastreada a versão exata de cada pacote que está instalado, assim o produto é 100% reproduzível mesmo que pacotes sejam atualizados pelos seus mantenedores.&lt;/p&gt;
&lt;p&gt;Isso resolve um problema muito específico que o &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt; deixou para trás. No package.json você pode definir para quais versões você quer atualizar (patch ou minor), usando a notação &lt;strong&gt;semver&lt;/strong&gt;, por exemplo:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;se você especifica &lt;code class=&quot;language-text&quot;&gt;~0.13.0&lt;/code&gt;, você quer atualizar apenas para versões patch: &lt;code class=&quot;language-text&quot;&gt;0.13.1&lt;/code&gt; está ok, mas &lt;code class=&quot;language-text&quot;&gt;0.14.0&lt;/code&gt; não está.&lt;/li&gt;
&lt;li&gt;se você especifica &lt;code class=&quot;language-text&quot;&gt;^0.13.0&lt;/code&gt;, você quer atualizar tanto para versões patch quanto minor: &lt;code class=&quot;language-text&quot;&gt;0.13.1&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;0.14.0&lt;/code&gt; e assim por diante.&lt;/li&gt;
&lt;li&gt;se você especifica &lt;code class=&quot;language-text&quot;&gt;0.13.0&lt;/code&gt;, essa é a versão exata que será utilizada, sempre&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Você não commita a pasta node_modules no seu Git, que geralmente é gigantesca, e quando você tenta replicar o projeto em outra máquina utilizando o comando &lt;code class=&quot;language-text&quot;&gt;npm install&lt;/code&gt;, se você especificou com a sintaxe &lt;code class=&quot;language-text&quot;&gt;~&lt;/code&gt; e uma versão patch do pacote foi lançada, ela que será instalada. O mesmo para &lt;code class=&quot;language-text&quot;&gt;^&lt;/code&gt; e versões inferiores.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Se você especifica versões exatas, como a &lt;code class=&quot;language-text&quot;&gt;0.13.0&lt;/code&gt; do exemplo, você não será afetado por esse problema.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Pode ser com você, ou com outra pessoa do outro lado do mundo tentando inicializar o projeto rodando &lt;code class=&quot;language-text&quot;&gt;npm install&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Então seu projeto original e o novo projeto recém inicializado são na verdade diferentes. Mesmo que uma versão patch ou minor não introduza mudanças que quebrem códigos antigos, nós todos sabemos que bugs podem (e vão) surgir.&lt;/p&gt;
&lt;p&gt;O &lt;code class=&quot;language-text&quot;&gt;package-lock.json&lt;/code&gt; grava na pedra a exata versão instalada de cada pacote, e o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; vai utilizar essas exatas versões quando rodar &lt;code class=&quot;language-text&quot;&gt;npm install&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Esse conceito não é novo, e gerenciadores de pacotes de outras linguages (como o Composer no PHP) utilizam desse sistema por anos.&lt;/p&gt;
&lt;p&gt;O arquivo &lt;code class=&quot;language-text&quot;&gt;package-lock.json&lt;/code&gt; precisa ser commitado no seu repositório Git, assim ele pode ser encontrado por outras pessoas, se o projeto é público ou você tem colaboradores, ou se você utiliza o GIT como fonte para deploys.&lt;/p&gt;
&lt;p&gt;As versões das dependências vão ser atualizadas no arquivo &lt;code class=&quot;language-text&quot;&gt;package-lock.json&lt;/code&gt; quando você rodar &lt;code class=&quot;language-text&quot;&gt;npm update&lt;/code&gt;.&lt;/p&gt;
&lt;h2&gt;Um exemplo&lt;/h2&gt;
&lt;p&gt;Essa é uma estrutura de exemplo de um arquivo &lt;code class=&quot;language-text&quot;&gt;package-lock.json&lt;/code&gt; que é obtida quando rodamos &lt;code class=&quot;language-text&quot;&gt;npm install cowsay&lt;/code&gt; em uma pasta vazia:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;requires&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;lockfileVersion&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;dependencies&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;ansi-regex&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;3.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &quot;https&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt;&lt;span class=&quot;token comment&quot;&gt;//registry.npmjs.org/ansi-regex/-/ansi-regex-3.&lt;/span&gt;
&lt;span class=&quot;token number&quot;&gt;0.0&lt;/span&gt;.tgz&quot;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha1-7QMXwyIGT3lGbAKWa922Bas32Zg=&quot;&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;cowsay&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;1.3.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://registry.npmjs.org/cowsay/-/cowsay-1.3.1.tgz&quot;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &quot;sha&lt;span class=&quot;token number&quot;&gt;512&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;-3&lt;/span&gt;PVFe&lt;span class=&quot;token number&quot;&gt;6&lt;/span&gt;FePVtPj&lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;HTeLin&lt;span class=&quot;token number&quot;&gt;9&lt;/span&gt;v&lt;span class=&quot;token number&quot;&gt;8&lt;/span&gt;WyLl+VmM&lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;l&lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;H/&lt;span class=&quot;token number&quot;&gt;5&lt;/span&gt;P+BTTDkM
Ajufp+&lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;F&lt;span class=&quot;token number&quot;&gt;9&lt;/span&gt;eLjzRnOHzVAYeIYFF&lt;span class=&quot;token number&quot;&gt;5&lt;/span&gt;po&lt;span class=&quot;token number&quot;&gt;5&lt;/span&gt;NjRrgefnRMQ==&quot;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;requires&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;get-stdin&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^5.0.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;optimist&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;~0.6.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;string-width&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;~2.1.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;strip-eof&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.0.0&quot;&lt;/span&gt;
      &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;get-stdin&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;5.0.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &quot;https&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt;&lt;span class=&quot;token comment&quot;&gt;//registry.npmjs.org/get-stdin/-/get-stdin-5.0.&lt;/span&gt;
&lt;span class=&quot;token number&quot;&gt;1.&lt;/span&gt;tgz&quot;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha1-Ei4WFZHiH/TFJTAwVpPyDmOTo5g=&quot;&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;is-fullwidth-code-point&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;2.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &quot;https&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt;&lt;span class=&quot;token comment&quot;&gt;//registry.npmjs.org/is-fullwidth-code-point/-/&lt;/span&gt;
is-fullwidth-code-point&lt;span class=&quot;token number&quot;&gt;-2.0&lt;/span&gt;.&lt;span class=&quot;token number&quot;&gt;0.&lt;/span&gt;tgz&quot;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha1-o7MKXE8ZkYMWeqq5O+764937ZU8=&quot;&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;minimist&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;0.0.10&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &quot;https&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt;&lt;span class=&quot;token comment&quot;&gt;//registry.npmjs.org/minimist/-/minimist-0.0.10&lt;/span&gt;
.tgz&quot;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha1-3j+YVD2/lggr5IrRoMfNqDYwHc8=&quot;&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;optimist&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;0.6.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://registry.npmjs.org/optimist/-/optimist-0.6.1.tgz&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha1-2j6nRob6IaGaERwybpDrFaAZZoY=&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;

      &lt;span class=&quot;token property&quot;&gt;&quot;requires&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;minimist&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;~0.0.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;wordwrap&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;~0.0.2&quot;&lt;/span&gt;
      &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;string-width&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;2.1.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://registry.npmjs.org/string-width/-/string-width-2.1.1.tgz&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha512-nOqH59deCq9SRHlxq1Aw85Jnt4w6KvLKqWVik6oA9ZklXLNIOlqg4F2yrT1MVaTjAqvVwdfeZ7w7aCvJD7ugkw==&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;requires&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;is-fullwidth-code-point&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^2.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;strip-ansi&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^4.0.0&quot;&lt;/span&gt;
      &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;strip-ansi&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;4.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://registry.npmjs.org/strip-ansi/-/strip-ansi-4.0.0.tgz&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha1-qEeQIusaw2iocTibY1JixQXuNo8=&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;requires&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;ansi-regex&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^3.0.0&quot;&lt;/span&gt;
      &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;strip-eof&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;1.0.0&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://registry.npmjs.org/strip-eof/-/strip-eof-1.0.0.tgz&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha1-u0P/VZim6wXYm1n80SnJgzE2Br8=&quot;&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;wordwrap&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;0.0.3&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://registry.npmjs.org/wordwrap/-/wordwrap-0.0.3.tgz&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha1-o9XabNXAvAAI03I0u68b7WMFkQc=&quot;&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Nós instalamos o &lt;code class=&quot;language-text&quot;&gt;cowsay&lt;/code&gt;, que depende de:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;get-stdin&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;optimist&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;string-width&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;strip-eof&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Por sua vez, esses pacotes dependem de outros pacotes, como podemos ver nos &lt;code class=&quot;language-text&quot;&gt;requires&lt;/code&gt; de alguns deles:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;ansi-regex&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;is-fullwidth-code-point&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;minimist&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;wordwrap&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;strip-eof&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Eles são adicionados ao arquivo em ordem alfabética, e cada um têm um campo &lt;code class=&quot;language-text&quot;&gt;version&lt;/code&gt;, um &lt;code class=&quot;language-text&quot;&gt;resolver&lt;/code&gt;, que aponta para a localização do pacote, e um &lt;code class=&quot;language-text&quot;&gt;integrity&lt;/code&gt;, que é uma string para validação do pacote.&lt;/p&gt;
&lt;h2&gt;Veja as versões instaladas de um pacote NPM&lt;/h2&gt;
&lt;p&gt;Para ver a última versão de todos os pacotes npm instalados, incluindo suas dependências:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; list&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;❯ &lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; list
/Users/joe/dev/node/cowsay
└─┬ cowsay@1.3.1
  ├── get-stdin@5.0.1
  ├─┬ optimist@0.6.1
  │ ├── minimist@0.0.10
  │ └── wordwrap@0.0.3
  ├─┬ string-width@2.1.1
  │ ├── is-fullwidth-code-point@2.0.0
  │ └─┬ strip-ansi@4.0.0
  │   └── ansi-regex@3.0.0
  └── strip-eof@1.0.0&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você também pode abrir o arquivo &lt;code class=&quot;language-text&quot;&gt;package-lock.json&lt;/code&gt;, mas você terá que ler muita informação desnecessária.&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;npm list -g&lt;/code&gt; tem o mesmo funcionamento, porém para pacotes instalados globalmente.&lt;/p&gt;
&lt;p&gt;Para obter obter apenas os pacotes top-level (basicamente aqueles que você pediu para o npm instalar e estão listados no &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;), execute &lt;code class=&quot;language-text&quot;&gt;npm list --depth=0&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;❯ &lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; list --depth&lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;
/Users/joe/dev/node/cowsay
└── cowsay@1.3.1&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você pode obter a versão de um pacote em específico fornecendo o nome dele:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;❯ &lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; list cowsay
/Users/joe/dev/node/cowsay
└── cowsay@1.3.1&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso também funciona para dependências dos pacotes instalados:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;❯ &lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; list minimist
/Users/joe/dev/node/cowsay
└─┬ cowsay@1.3.1
  └─┬ optimist@0.6.1
    └── minimist@0.0.10&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Se você quer ver qual é a última versão disponível de um pacote no repositório npm, execute &lt;code class=&quot;language-text&quot;&gt;npm view [package_name] version&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;❯ &lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; view cowsay version

&lt;span class=&quot;token number&quot;&gt;1.3&lt;/span&gt;.1&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Instale uma versão mais antiga de um pacote NPM&lt;/h2&gt;
&lt;p&gt;Você pode instalar uma versão antiga de um pacote npm usando a sintaxe &lt;code class=&quot;language-text&quot;&gt;@&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;package&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;@&lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;version&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; cowsay&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;instala a versão 1.3.1 (no momento de escrita).&lt;/p&gt;
&lt;p&gt;Instale a versão 1.2.0 assim:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; cowsay@1.2.0&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;O mesmo pode ser feito com pacotes globais:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; -g webpack@4.16.4&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você também pode estar interessado em listar todas as versões anteriores de um pacote. Você pode fazer isso executando &lt;code class=&quot;language-text&quot;&gt;npm view &amp;lt;package&amp;gt; versions&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;❯ &lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; view cowsay versions

&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;1.0.0&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.0.1&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.0.2&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.0.3&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.0&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.1&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.2&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.3&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.4&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.5&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.6&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.7&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.8&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.1.9&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.2.0&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.2.1&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.3.0&apos;&lt;/span&gt;,
  &lt;span class=&quot;token string&quot;&gt;&apos;1.3.1&apos;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Atualize todas as versões do Node.js para a última versão.&lt;/h2&gt;
&lt;p&gt;Quando você instala um pacote utilizando &lt;code class=&quot;language-text&quot;&gt;npm install &amp;lt;packagename&amp;gt;&lt;/code&gt;, a última versão disponível do pacote é baixada e colocada na pasta &lt;code class=&quot;language-text&quot;&gt;node_modules&lt;/code&gt;, e uma entrada correspondente é adicionada nos arquivos &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;package-lock.json&lt;/code&gt; presentes na pasta atual.&lt;/p&gt;
&lt;p&gt;o npm calcula as dependências e também instala a última versão delas.&lt;/p&gt;
&lt;p&gt;Digamos que você instale o &lt;a href=&quot;https://www.npmjs.com/package/cowsay&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;cowsay&lt;/code&gt;&lt;/a&gt;, uma ferramenta de linha de comando bem legal que te permite fazer uma vaca falar &lt;em&gt;coisas&lt;/em&gt;.&lt;/p&gt;
&lt;p&gt;Quando você roda &lt;code class=&quot;language-text&quot;&gt;npm install cowsay&lt;/code&gt;, essa entrada é adicionada no arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;dependencies&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;cowsay&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.3.1&quot;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e esse é um trecho do &lt;code class=&quot;language-text&quot;&gt;package-lock.json&lt;/code&gt;, onde removemos as subdependências para facilitar a leitura:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;json&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-json line-numbers&quot;&gt;&lt;code class=&quot;language-json&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;requires&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;lockfileVersion&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token property&quot;&gt;&quot;dependencies&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token property&quot;&gt;&quot;cowsay&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;version&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;1.3.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;resolved&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;https://registry.npmjs.org/cowsay/-/cowsay-1.3.1.tgz&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;integrity&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;sha512-3PVFe6FePVtPj1HTeLin9v8WyLl+VmM1l1H/5P+BTTDkMAjufp+0F9eLjzRnOHzVAYeIYFF5po5NjRrgefnRMQ==&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      &lt;span class=&quot;token property&quot;&gt;&quot;requires&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;get-stdin&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^5.0.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;optimist&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;~0.6.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;string-width&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;~2.1.1&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
        &lt;span class=&quot;token property&quot;&gt;&quot;strip-eof&quot;&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;^1.0.0&quot;&lt;/span&gt;
      &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Agora esses 2 arquivos nos dizem que instalamos a versão &lt;code class=&quot;language-text&quot;&gt;1.3.1&lt;/code&gt; do cowsay, e nossa regra para atualizações é &lt;code class=&quot;language-text&quot;&gt;^1.3.1&lt;/code&gt;, o que o npm pode atualizar para versões patch e minor: &lt;code class=&quot;language-text&quot;&gt;1.3.2&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;1.4.0&lt;/code&gt; e assim por diante.&lt;/p&gt;
&lt;p&gt;Se há uma nova versão minor ou patch e nós digitamos &lt;code class=&quot;language-text&quot;&gt;npm update&lt;/code&gt;, a versão instalada é atualizada, e o arquivo &lt;code class=&quot;language-text&quot;&gt;package-lock.json&lt;/code&gt; rapidamente se atualiza com a nova versão.&lt;/p&gt;
&lt;p&gt;o &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt; permanece sem alterações.&lt;/p&gt;
&lt;p&gt;Para descobrir novas atualizações dos pacotes, rode &lt;code class=&quot;language-text&quot;&gt;npm outdated&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Aqui está uma lista de alguns pacotes desatualizados em um repositório que não recebe atualizações há um bom tempo:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/e967736f8d105e64c22d80ce7a42f52a/5333d/outdated-packages.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 66.28041714947857%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAANCAYAAACpUE5eAAAACXBIWXMAAAsSAAALEgHS3X78AAACyUlEQVQ4y6WT204TURSGMUa90bsWSsS20+4edmf2nHZnplSglIMdDJB4gUjLQXkAE4kSHkIeAb3xIZTGQ0yMd95oCyHxBtQAvoFM9u+eIZ7CpSv58u9kJl/WXmump0fW9w/vzM7nN9P7h98a375+8b9I9g/2/U6343/qfPR3d3f8brfr73R3/U5nxz84+OofHx/7R0dH/uHhYUPm9N7ent3zqxZmZ58vr8xjcWkZd1fu4d5dicxWcxHNOy3M374jmcfc3BwWFuaxtLSIVquFZrMZsbq6is3Nxy8BnAt956mqbXvVETh25USlTCjJrMhni6JA6Cm5osgoGZEnRJQoEYViRvT394uBgQERi8VO5Blra2uvpfBCJByvV7dvzU7A4ewklU6LZCoVkUolRSaTEbVaTbiuK9yxquCuI0Yqw2J8fELMzswI0zRPCCHY2Nj4Ixx0tHZjtAxDLQRFmgOl+Qgpg6IoqHgVWGUbpKqC6iV4ahljY+OY8n14nheE7/0jHHL19tSoC5drgWFSMFYE04uRLJlMwuYcpm6AcArNYvCYg3q9jptTU3Ad56xweMRs+40KhobMwJRCw6AIk3PZESWR0DYtEKcEzdZR1b2/hO5ZYXVQb0/UHQx6emBaJbgeQ6l0euV0Og3LtqEzHcSmKOkqHNVGbaSGyclJlDk/K7zOtfbkdY7BMguUjCIXoYi0kpZLSUU4jiNM2xKyQyGFosIcUR+ti8aNG+Gzs0KLFl5UDB35fP5HNkOCEEJyp2Rzgc6MQGVakGX5oEALgUGZHI0VcNsOKKU/stlsKHz1W8hN/tZzqmAlA5bOYWimzDK46cBkHCrV5CwpciQXLeoX4ThCZCNYX19//1t47erV+4lE3zP5kW7F47Enkqexv4jH4xG9vb3/0NfX90TmViKReDY9M/Pg4aP1Cz0knQx/l4uSy5Ir/8Elybmf9WKE+vPUqtIAAAAASUVORK5CYII=&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;lista exibindo as versões mais atualizadas de alguns pacotes&quot;
        title=&quot;lista exibindo as versões mais atualizadas de alguns pacotes&quot;
        src=&quot;/static/e967736f8d105e64c22d80ce7a42f52a/799d3/outdated-packages.png&quot;
        srcset=&quot;/static/e967736f8d105e64c22d80ce7a42f52a/00d96/outdated-packages.png 148w,
/static/e967736f8d105e64c22d80ce7a42f52a/0b23c/outdated-packages.png 295w,
/static/e967736f8d105e64c22d80ce7a42f52a/799d3/outdated-packages.png 590w,
/static/e967736f8d105e64c22d80ce7a42f52a/5333d/outdated-packages.png 863w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Algumas dessas atualizações são para versões major. Executando &lt;code class=&quot;language-text&quot;&gt;npm update&lt;/code&gt; elas não serão atualizadas. Versões major nunca são atualizadas desse jeito porque elas (por definição) introduzem mudanças sujeitas a quebras em versões antigas, e o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; quer nos poupar desse problema.&lt;/p&gt;
&lt;p&gt;Para atualizar para uma versão major desses pacotes, instale o pacote &lt;code class=&quot;language-text&quot;&gt;npm-check-updates&lt;/code&gt; globalmente:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; -g npm-check-updates&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e então rode:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;ncu -u&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;isso irá atualizar as versões no &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;, tanto &lt;code class=&quot;language-text&quot;&gt;dependencies&lt;/code&gt; quanto &lt;code class=&quot;language-text&quot;&gt;devDependencies&lt;/code&gt;, assim o npm poderá instalar as versões major.&lt;/p&gt;
&lt;p&gt;Agora você está pronto para executar as atualizações:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; update&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Se você só baixou o projeto sem as dependências do &lt;code class=&quot;language-text&quot;&gt;node_modules&lt;/code&gt; e quer instalar as novas versões, basta rodar&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Usando Semantic Versioning no NPM&lt;/h2&gt;
&lt;p&gt;Se há uma coisa incrível nos pacotes Node.js, é que todos eles permitem utilizar Versionamento Semântico em suas numerações de versão.&lt;/p&gt;
&lt;p&gt;O Versionamento Semântico é um conceito simples: todas versões têm 3 digitos: &lt;code class=&quot;language-text&quot;&gt;x.y.z&lt;/code&gt;.&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;o primeiro digito é a versão major&lt;/li&gt;
&lt;li&gt;o segundo digito é a versão minor&lt;/li&gt;
&lt;li&gt;o terceiro digito é a versão patch&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Quando você cria uma nova versão, você não aumenta um número como bem entender, existem algumas regras:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;você aumenta a versão major quando você cria mudanças de API incompatíveis&lt;/li&gt;
&lt;li&gt;você aumenta a versão minor quando você adiciona uma funcionalidade compatível com versões anteriores&lt;/li&gt;
&lt;li&gt;você aumenta a versão patch quando você arruma bugs sem quebrar versões anteriores&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Essa convenção é adotada em todas linguagens de programação, e é muito importante que todo pacote &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; a siga, pois o sistema como um todo depende disso.&lt;/p&gt;
&lt;p&gt;Por que isso é tão importante?&lt;/p&gt;
&lt;p&gt;Porque o &lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt; define algumas regras que podemos usar no &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt; para escolher quais versões podem ser atualizadas ao rodar &lt;code class=&quot;language-text&quot;&gt;npm update&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;As regras utilizam esses símbolos:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;^&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;~&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;&amp;gt;&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;&amp;gt;=&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;&amp;lt;&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;&amp;lt;=&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;=&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;-&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;||&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Vamos ver essas regras em detalhes:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;^&lt;/code&gt;:  Só vai fazer atualizações que não alterem o número mais a esquerda diferente de zero. Se você definir &lt;code class=&quot;language-text&quot;&gt;^0.13.0&lt;/code&gt;, ao rodar &lt;code class=&quot;language-text&quot;&gt;npm update&lt;/code&gt;, ele pode atualizar para &lt;code class=&quot;language-text&quot;&gt;0.13.1&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;0.13.2&lt;/code&gt;, e assim por diante, mas não para &lt;code class=&quot;language-text&quot;&gt;0.14.0&lt;/code&gt; ou posteriores. Se você definir &lt;code class=&quot;language-text&quot;&gt;^1.13.0&lt;/code&gt;, ao rodar &lt;code class=&quot;language-text&quot;&gt;npm update&lt;/code&gt;, ele pode atualizar para &lt;code class=&quot;language-text&quot;&gt;1.13.1&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;1.14.0&lt;/code&gt; e assim por diante, mas não para &lt;code class=&quot;language-text&quot;&gt;2.0.0&lt;/code&gt; ou posterior.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;~&lt;/code&gt;: se você definir &lt;code class=&quot;language-text&quot;&gt;~0.13.0&lt;/code&gt;, ao rodar &lt;code class=&quot;language-text&quot;&gt;npm update&lt;/code&gt; ele pode atualizar para versões patch: &lt;code class=&quot;language-text&quot;&gt;0.13.1&lt;/code&gt; está ok, mas &lt;code class=&quot;language-text&quot;&gt;0.14.0&lt;/code&gt; não está.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;&amp;gt;&lt;/code&gt;: aceita qualquer versão maior que a especificada&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;&amp;gt;=&lt;/code&gt;: aceita qualquer versão maior ou igual a especificada&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;&amp;lt;=&lt;/code&gt;: aceita qualquer versão menor ou igual a especificada&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;&amp;lt;&lt;/code&gt;: aceita qualquer versão menor que a especificada&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;=&lt;/code&gt;: aceita aquela exata versão&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;-&lt;/code&gt;: aceita qualquer versão dentro de um intervalo. Exemplo: &lt;code class=&quot;language-text&quot;&gt;2.1.0 - 2.6.2&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;||&lt;/code&gt;: combina restrições. Exemplo: &lt;code class=&quot;language-text&quot;&gt;&amp;lt; 2.1 || &amp;gt; 2.6&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Você pode combinar algumas dessas notações, por exemplo, utilize &lt;code class=&quot;language-text&quot;&gt;1.0.0 || &amp;gt;=1.1.0 &amp;lt;1.2.0&lt;/code&gt; para usar 1.0.0 ou uma versão maior ou igual a 1.1.0, porém menor que 1.2.0.&lt;/p&gt;
&lt;p&gt;Também há outras regras:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;sem símbolo: aceita apenas a versão especificada (&lt;code class=&quot;language-text&quot;&gt;1.2.1&lt;/code&gt;)&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;latest&lt;/code&gt;: usa a versão mais recente disponível&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;Desinstalando pacotes NPM&lt;/h2&gt;
&lt;p&gt;Para desinstalar um pacote que você tenha instalado previamente de forma &lt;strong&gt;local&lt;/strong&gt; (usando &lt;code class=&quot;language-text&quot;&gt;npm install &amp;lt;package-name&amp;gt;&lt;/code&gt; na pasta &lt;code class=&quot;language-text&quot;&gt;node_modules&lt;/code&gt;), execute&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; uninstall &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;package-name&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;a partir da pasta raiz do projeto (a pasta que contêm a pasta node_modules).&lt;/p&gt;
&lt;p&gt;Usando a flag &lt;code class=&quot;language-text&quot;&gt;-S&lt;/code&gt;, ou &lt;code class=&quot;language-text&quot;&gt;--save&lt;/code&gt;, essa operação também irá remover a referência no arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Se o pacote era uma dependência de desenvolvimento, listada no devDependencies do arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;, você deve utilizar a flag &lt;code class=&quot;language-text&quot;&gt;-D&lt;/code&gt; / &lt;code class=&quot;language-text&quot;&gt;--save-dev&lt;/code&gt;para removê-la do arquivo.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; uninstall -S &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;package-name&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; uninstall -D &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;package-name&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Se o pacote está instalado &lt;strong&gt;globalmente&lt;/strong&gt;, você precisa adicionar a flag &lt;code class=&quot;language-text&quot;&gt;-g&lt;/code&gt; / &lt;code class=&quot;language-text&quot;&gt;--global&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; uninstall -g &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt;package-name&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; uninstall -g webpack&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e você pode rodar esse comando em qualquer lugar do seu sistema pois a pasta que você está não importa.
and you can run this command from anywhere you want on your system because the folder where you currently are does not matter.&lt;/p&gt;
&lt;h2&gt;NPM: pacotes globais ou locais&lt;/h2&gt;
&lt;p&gt;A principal diferença entre pacotes locais e globais é:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;strong&gt;pacotes locais&lt;/strong&gt; são instalados no diretório em que você executa &lt;code class=&quot;language-text&quot;&gt;npm install &amp;lt;package-name&amp;gt;&lt;/code&gt;, e eles são inseridos na pasta &lt;code class=&quot;language-text&quot;&gt;node_modules&lt;/code&gt; desse diretório.&lt;/li&gt;
&lt;li&gt;&lt;strong&gt;pacotes globais&lt;/strong&gt; são todos colocados em único lugar do seu sistema (dependendo da sua configuração), independentemente de onde você execute &lt;code class=&quot;language-text&quot;&gt;npm install -g &amp;lt;package-name&amp;gt;&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;No seu código você só pode importar pacotes locais:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;package-name&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;então quando instalar um ou outro?&lt;/p&gt;
&lt;p&gt;No geral, &lt;strong&gt;todos os pacotes devem ser instalados localmente&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Isso garante que você possa ter dúzias de aplicações no seu computador, todas rodando com uma versão diferente de cada pacote se necessário.&lt;/p&gt;
&lt;p&gt;Atualizar um pacote global fará com que todos seus projetos usem a nova versão, e como você pode imaginar isso pode causar pesadelos em termos de manutenção, pois alguns pacotes podem quebrar.&lt;/p&gt;
&lt;p&gt;Todos projetos tem sua própria versão local de um pacote, mesmo que isso possa parecer um desperdício de recursos, é algo pequeno comparado as possíveis consequências.&lt;/p&gt;
&lt;p&gt;Um pacote &lt;strong&gt;deve ser instalado globalmente&lt;/strong&gt; quando ele fornece um comando executável que possa ser rodado pelo terminal (CLI), e é reutilizado entre projetos.&lt;/p&gt;
&lt;p&gt;Você também pode instalar comandos executáveis localmente e rodá-los usando o npx, porém alguns pacotes funcionam melhor instalados de forma global.&lt;/p&gt;
&lt;p&gt;Alguns otimos exemplos de pacotes globais populares que você pode conhecer:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;npm&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;create-react-app&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;vue-cli&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;grunt-cli&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;mocha&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;react-native-cli&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;gatsby-cli&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;forever&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;nodemon&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Você provavelmente já tem alguns deles instalados globalmente no seu sistema. Você pode conferir executando&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; list -g --depth &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;no seu terminal.&lt;/p&gt;
&lt;h2&gt;npm: diferença entre dependencies e devDependencies&lt;/h2&gt;
&lt;p&gt;Quando você instala um pacote usando &lt;code class=&quot;language-text&quot;&gt;npm install &amp;lt;package-name&amp;gt;&lt;/code&gt;, ele está sendo instalado como uma &lt;strong&gt;dependência&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;O pacote é listado automaticamente no arquivo package.json, na lista de &lt;code class=&quot;language-text&quot;&gt;dependencies&lt;/code&gt; (a partir do npm 5: antes você tinha que especificar manualmente com &lt;code class=&quot;language-text&quot;&gt;--save&lt;/code&gt;).&lt;/p&gt;
&lt;p&gt;Quandi você adiciona a flag &lt;code class=&quot;language-text&quot;&gt;-D&lt;/code&gt;, ou &lt;code class=&quot;language-text&quot;&gt;--save-dev&lt;/code&gt;, você está instalado como uma dependência de desenvolvimento, que é adicionada na lista de &lt;code class=&quot;language-text&quot;&gt;devDependencies&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Dependências de desenvolvimento são entendidas como pacotes apenas para desenvolver, não são necessárias em produção. Por exemplo pacotes de teste, webpack ou Babel.&lt;/p&gt;
&lt;p&gt;Quando você vai para produção, se digitar &lt;code class=&quot;language-text&quot;&gt;npm install&lt;/code&gt; e a pasta conter um arquivo &lt;code class=&quot;language-text&quot;&gt;package.json&lt;/code&gt;, elas são instaladas, pois o npm assume que é um deploy de desenvolvimento.&lt;/p&gt;
&lt;p&gt;Você precisa passar a flag &lt;code class=&quot;language-text&quot;&gt;--production&lt;/code&gt; (&lt;code class=&quot;language-text&quot;&gt;npm install --production&lt;/code&gt;) para evitar instalar essas dependências de desenvolvimento.&lt;/p&gt;
&lt;h2&gt;Conhecendo o NPX&lt;/h2&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;npx&lt;/code&gt; é um comando poderoso que está disponível no &lt;strong&gt;npm&lt;/strong&gt; a partir da versão 5.2, lançada em Julho de 2017.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Se você não quer instalar o npm, você pode &lt;a href=&quot;https://www.npmjs.com/package/npx&quot;&gt;instalar o npx como um pacote standalone&lt;/a&gt;&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;O &lt;code class=&quot;language-text&quot;&gt;npx&lt;/code&gt; permite rodar seu código feito com Node.js e publicado nos registros do npm.&lt;/p&gt;
&lt;h2&gt;Rode comandos locais facilmente&lt;/h2&gt;
&lt;p&gt;Desenvolvedores Node.js costumam publicar a maioria dos comandos executáveis como pacotes globais, pois assim é garantido que eles estejam salvos no &lt;code class=&quot;language-text&quot;&gt;path&lt;/code&gt; e executados imediatamente.&lt;/p&gt;
&lt;p&gt;Isso é bem chato poque você não pode instalar versões diferentes do mesmo comando.&lt;/p&gt;
&lt;p&gt;Ao rodar &lt;code class=&quot;language-text&quot;&gt;npx nomedocomando&lt;/code&gt; a referência correta do comando dentro da pasta &lt;code class=&quot;language-text&quot;&gt;node_modules&lt;/code&gt; do projeto é encontrada automaticamente, e sem a necessidade de saber o caminho exato, e sem a necessidade de ter o pacote instalado globalmente e no &lt;code class=&quot;language-text&quot;&gt;path&lt;/code&gt; do usuário.&lt;/p&gt;
&lt;h2&gt;Execução de comandos sem instalação&lt;/h2&gt;
&lt;p&gt;Outro excelente recurso do &lt;code class=&quot;language-text&quot;&gt;npx&lt;/code&gt; é permitir rodar comandos sem tê-los instalados.&lt;/p&gt;
&lt;p&gt;Isso é extremamente útil, porque:&lt;/p&gt;
&lt;ol&gt;
&lt;li&gt;você não precisa instalar nada&lt;/li&gt;
&lt;li&gt;você pode rodar diferentes versões do mesmo comando, usando a sintaxe &lt;code class=&quot;language-text&quot;&gt;@version&lt;/code&gt;&lt;/li&gt;
&lt;/ol&gt;
&lt;p&gt;Uma demonstração típica do uso do &lt;code class=&quot;language-text&quot;&gt;npx&lt;/code&gt; é através do comando &lt;code class=&quot;language-text&quot;&gt;cowsay&lt;/code&gt;. O &lt;code class=&quot;language-text&quot;&gt;cowsay&lt;/code&gt; vai imprimir uma vaca na tela dizendo o que você digitou no comando. Por exemplo:&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;cowsay &amp;quot;Salve pra firma&amp;quot;&lt;/code&gt; vai resultar em&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;console&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-console line-numbers&quot;&gt;&lt;code class=&quot;language-console&quot;&gt; _________________
&amp;lt; Salve pra firma &amp;gt;
 -----------------
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso só funciona se você tiver o comando &lt;code class=&quot;language-text&quot;&gt;cowsay&lt;/code&gt; previamente instalado pelo npm. Caso contrário você receberá um erro ao tentar rodar o comando.&lt;/p&gt;
&lt;p&gt;O &lt;code class=&quot;language-text&quot;&gt;npx&lt;/code&gt; permite que você rode o comando sem tê-lo instalado localmente:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;npx cowsay &lt;span class=&quot;token string&quot;&gt;&quot;Salve pra firma&quot;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Outros cenários de exemplo:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;rodar a CLI do &lt;code class=&quot;language-text&quot;&gt;vue&lt;/code&gt; para criar novas aplicações: &lt;code class=&quot;language-text&quot;&gt;npx @vue/cli create my-vue-app&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;criar uma aplicação React usando &lt;code class=&quot;language-text&quot;&gt;create-react-app&lt;/code&gt;: &lt;code class=&quot;language-text&quot;&gt;npx create-react-app my-react-app&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Uma vez executado, o código baixado será apagado.&lt;/p&gt;
&lt;h2&gt;Rodando um código em uma versão difente do Node.js&lt;/h2&gt;
&lt;p&gt;Utilize o &lt;code class=&quot;language-text&quot;&gt;@&lt;/code&gt; para especificar a versão, e combine-o com uma &lt;a href=&quot;https://www.npmjs.com/package/node&quot;&gt;versão empacotada do &lt;code class=&quot;language-text&quot;&gt;node&lt;/code&gt;&lt;/a&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;npx node@10 -v &lt;span class=&quot;token comment&quot;&gt;#v10.18.1&lt;/span&gt;
npx node@12 -v &lt;span class=&quot;token comment&quot;&gt;#v12.14.1&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso ajuda a evitar ferramentas como o &lt;code class=&quot;language-text&quot;&gt;nvm&lt;/code&gt; ou outros gerenciadores de versão para Node.js.&lt;/p&gt;
&lt;h2&gt;Rodando códigos diretamente de uma URL&lt;/h2&gt;
&lt;p&gt;O &lt;code class=&quot;language-text&quot;&gt;npx&lt;/code&gt; não te limita aos pacotes publicados nos registros do npm.&lt;/p&gt;
&lt;p&gt;Você pode rodar códigos de um gist no GitHub, por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;npx https://gist.github.com/zkat/4bc19503fe9e9309e2bfaa2c58074d32&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Mas é claro que você precisa ter cuidado ao rodar códigos que estão fora do seu controle, com grandes poderes vem grandes responsabilidades.&lt;/p&gt;
&lt;h2&gt;O Event Loop do Node.js&lt;/h2&gt;
&lt;h2&gt;Introdução&lt;/h2&gt;
&lt;p&gt;O &lt;strong&gt;Evnet Loop&lt;/strong&gt; é um dos aspectos do Node.js mais importantes de se entender.&lt;/p&gt;
&lt;p&gt;Por que ele é tão importante? Porque ele explica como o Node.js pode ser assíncrono e ter I/O não bloqueante, e também explica o diferencial do Node.js, o quê fez dele bem-sucedido.&lt;/p&gt;
&lt;p&gt;O código JavaScript Node.js roda em uma única thread. Há apenas uma coisa acontecendo por vez.&lt;/p&gt;
&lt;p&gt;Essa é uma limitação que na verdade é bem útil, pois ela simplifica muito como você programa sem se preocupar com problemas de concorrência.&lt;/p&gt;
&lt;p&gt;Você só precisa prestar atenção em como escrever seu código e evitar qualquer coisa que possa bloquear a thread, como chamadas de rede síncronas ou loops infinitos.&lt;/p&gt;
&lt;p&gt;No geral, na maioria dos browsers existe um event loop para cada aba aberta, para tratar cada processo de forma isolada e evitar que uma página web com loops infinitos ou processamento pesado bloqueie o browser por completo.&lt;/p&gt;
&lt;p&gt;O ambiente de execução gerencia múltiplos event loops concorrentes, para fazer chamadas à APIs por exemplo. Web Workers rodam em seus próprios event loops também.&lt;/p&gt;
&lt;p&gt;Você precisa se preocupar principalmente com que seu código rode um único event loop, e escrever o código com isso em mente a fim de evitar bloquear a thread.&lt;/p&gt;
&lt;h2&gt;Bloqueando o event loop&lt;/h2&gt;
&lt;p&gt;Qualquer código JavaScript que demore muito para retornar ao controle do event loop irá bloquear a execução de algum código JavaScript na página, até mesmo bloquear a thread de UI, impossibilitando o usuário de clicar, rolar, e etc.&lt;/p&gt;
&lt;p&gt;Quase todas primitivas de I/O no JavaScript são não bloqueantes. Requisições de rede, operações no filesystem, e etc. Ser bloqueante é a exceção, e esse é o porquê do JavaScript ser extremamente baseado em callbacks, e mais recentemente em promises e async/await.&lt;/p&gt;
&lt;h2&gt;A call stack&lt;/h2&gt;
&lt;p&gt;A call stack (pilha de chamadas) é uma fila do tipo LIFO (Last In, First Out, que em português significa último a entrar, primeiro a sair).&lt;/p&gt;
&lt;p&gt;O event loop checa continuamente a &lt;strong&gt;call stack&lt;/strong&gt; para ver se há qualquer função que precise rodar.&lt;/p&gt;
&lt;p&gt;Enquanto faz isso, ele adiciona na call stack qualquer chamada de função que encontrar e executa cada uma em ordem.&lt;/p&gt;
&lt;p&gt;Sabe quando ocorre um erro e no debugger ou no console do browser aparece uma sequência hierárquica de nomes de funções? Basicamente o browser procura os nomes das funções na call stack para te informar qual função originou a chamada corrente:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/e4594b6135efd353b44770f748fdccd5/ed9ca/exception-call-stack.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 103.88513513513513%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;Exception na call stack&quot;
        title=&quot;Exception na call stack&quot;
        src=&quot;/static/e4594b6135efd353b44770f748fdccd5/799d3/exception-call-stack.png&quot;
        srcset=&quot;/static/e4594b6135efd353b44770f748fdccd5/00d96/exception-call-stack.png 148w,
/static/e4594b6135efd353b44770f748fdccd5/0b23c/exception-call-stack.png 295w,
/static/e4594b6135efd353b44770f748fdccd5/799d3/exception-call-stack.png 590w,
/static/e4594b6135efd353b44770f748fdccd5/ed9ca/exception-call-stack.png 592w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;h2&gt;Uma explicação simples sobre o event loop&lt;/h2&gt;
&lt;p&gt;Dado esse exemplo:&lt;/p&gt;
&lt;iframe
  title=&quot;A simple event loop explanation&quot;
  src=&quot;https://glitch.com/embed/#!/embed/nodejs-dev-0029-01?path=server.js&amp;previewSize=20&amp;attributionHidden=true&amp;sidebarCollapsed=true&quot;
  alt=&quot;nodejs-dev-0029-01 on Glitch&quot;
  style=&quot;height: 400px; width: 100%; border: 0;&quot;&gt;
&lt;/iframe&gt;
&lt;!--```js
const bar = () =&gt; console.log(&apos;bar&apos;)

const baz = () =&gt; console.log(&apos;baz&apos;)

const foo = () =&gt; {
  console.log(&apos;foo&apos;)
  bar()
  baz()
}

foo()
```

Esse código imprime

```txt
foo
bar
baz
```

como esperado.--&gt;
&lt;p&gt;Quando esse código roda, primeiro é chamada &lt;code class=&quot;language-text&quot;&gt;foo()&lt;/code&gt;. Dentro de &lt;code class=&quot;language-text&quot;&gt;foo()&lt;/code&gt; nós chamamos &lt;code class=&quot;language-text&quot;&gt;bar()&lt;/code&gt;, e então nós chamamos &lt;code class=&quot;language-text&quot;&gt;baz()&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Nesse ponto a call stack se parece com isso:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/270ebeb6dbfa7d613152b71257c72a9e/4c6ed/call-stack-first-example.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 104.48113207547169%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;Primeiro exemplo de Call stack&quot;
        title=&quot;Primeiro exemplo de Call stack&quot;
        src=&quot;/static/270ebeb6dbfa7d613152b71257c72a9e/799d3/call-stack-first-example.png&quot;
        srcset=&quot;/static/270ebeb6dbfa7d613152b71257c72a9e/00d96/call-stack-first-example.png 148w,
/static/270ebeb6dbfa7d613152b71257c72a9e/0b23c/call-stack-first-example.png 295w,
/static/270ebeb6dbfa7d613152b71257c72a9e/799d3/call-stack-first-example.png 590w,
/static/270ebeb6dbfa7d613152b71257c72a9e/2a3d6/call-stack-first-example.png 885w,
/static/270ebeb6dbfa7d613152b71257c72a9e/ae92f/call-stack-first-example.png 1180w,
/static/270ebeb6dbfa7d613152b71257c72a9e/4c6ed/call-stack-first-example.png 1272w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;O event loop olha em toda iteração se há algo na call stack, e o executa:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 466px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/ca404c319c6fc595497d5dc097d469ff/c5652/execution-order-first-example.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 165.0214592274678%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;Ordem de execução do primeiro exemplo&quot;
        title=&quot;Ordem de execução do primeiro exemplo&quot;
        src=&quot;/static/ca404c319c6fc595497d5dc097d469ff/c5652/execution-order-first-example.png&quot;
        srcset=&quot;/static/ca404c319c6fc595497d5dc097d469ff/00d96/execution-order-first-example.png 148w,
/static/ca404c319c6fc595497d5dc097d469ff/0b23c/execution-order-first-example.png 295w,
/static/ca404c319c6fc595497d5dc097d469ff/c5652/execution-order-first-example.png 466w&quot;
        sizes=&quot;(max-width: 466px) 100vw, 466px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;até que a call stack esteja vazia.&lt;/p&gt;
&lt;h2&gt;Enfileirando a execução de funções&lt;/h2&gt;
&lt;p&gt;O exemplo acima parece normal, não há nada de especial sobre ele: o JavaScript encontra coisas para executar, e as executa em ordem.&lt;/p&gt;
&lt;p&gt;Vamos ver como adiar uma função até que a stack esteja vazia.&lt;/p&gt;
&lt;p&gt;O caso de uso do &lt;code class=&quot;language-text&quot;&gt;setTimeout(() =&amp;gt; {}, 0)&lt;/code&gt; é chamar uma função, mas só executá-la assim que todas outras funções no código tenham executado.&lt;/p&gt;
&lt;p&gt;Veja esse exemplo:&lt;/p&gt;
&lt;iframe
  title=&quot;Queuing function execution&quot;
  src=&quot;https://glitch.com/embed/#!/embed/nodejs-dev-0029-02?path=server.js&amp;previewSize=20&amp;attributionHidden=true&amp;sidebarCollapsed=true&quot;
  alt=&quot;nodejs-dev-0029-02 on Glitch&quot;
  style=&quot;height: 400px; width: 100%; border: 0;&quot;&gt;
&lt;/iframe&gt;
&lt;!--```js
const bar = () =&gt; console.log(&apos;bar&apos;)

const baz = () =&gt; console.log(&apos;baz&apos;)

const foo = () =&gt; {
  console.log(&apos;foo&apos;)
  setTimeout(bar, 0)
  baz()
}

foo()
```--&gt;
&lt;p&gt;Para nossa surpresa, esse código imprime:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;foo
baz
bar&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Quando esse código roda, primeiro foo() é chamada. Dentro de foo() nós chamamos setTimeout, passando &lt;code class=&quot;language-text&quot;&gt;bar&lt;/code&gt; como um argumento, e nós instruimos a rodá-la imediatamente, o mais rápido possível, passando 0 como o tempo de contagem. E então nós chamamos baz().&lt;/p&gt;
&lt;p&gt;Nesse ponto a call stack se parece com isso:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/be55515b9343074d00b43de88c495331/962ce/call-stack-second-example.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 95.33898305084745%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;Segundo exemplo de Call stack&quot;
        title=&quot;Segundo exemplo de Call stack&quot;
        src=&quot;/static/be55515b9343074d00b43de88c495331/799d3/call-stack-second-example.png&quot;
        srcset=&quot;/static/be55515b9343074d00b43de88c495331/00d96/call-stack-second-example.png 148w,
/static/be55515b9343074d00b43de88c495331/0b23c/call-stack-second-example.png 295w,
/static/be55515b9343074d00b43de88c495331/799d3/call-stack-second-example.png 590w,
/static/be55515b9343074d00b43de88c495331/2a3d6/call-stack-second-example.png 885w,
/static/be55515b9343074d00b43de88c495331/962ce/call-stack-second-example.png 944w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Aqui temos a ordem de execução de todas as funções no nosso programa:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 470px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/585ff3207d814911a7e44d55fbde483b/15e5b/execution-order-second-example.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 181.06382978723403%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;Ordem de execução do segundo exemplo&quot;
        title=&quot;Ordem de execução do segundo exemplo&quot;
        src=&quot;/static/585ff3207d814911a7e44d55fbde483b/15e5b/execution-order-second-example.png&quot;
        srcset=&quot;/static/585ff3207d814911a7e44d55fbde483b/00d96/execution-order-second-example.png 148w,
/static/585ff3207d814911a7e44d55fbde483b/0b23c/execution-order-second-example.png 295w,
/static/585ff3207d814911a7e44d55fbde483b/15e5b/execution-order-second-example.png 470w&quot;
        sizes=&quot;(max-width: 470px) 100vw, 470px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Por que isso está acontecendo?&lt;/p&gt;
&lt;h2&gt;A Message Queue&lt;/h2&gt;
&lt;p&gt;Quando setTimeout() é chamado, o Browser ou o Node.js começa a contagem. Uma vez que ela encerre, nesse caso imediatamente pois definimos 0 como parâmetro, a função callback é colocada na &lt;strong&gt;Message Queue&lt;/strong&gt; (fila de mensagens).&lt;/p&gt;
&lt;p&gt;A Message Queue também é onde estão eventos iniciados pelo usuário, como clicks ou pressionamento de teclas, ou respostas de requisições enfileiradas. antes do seu código ter a oportunidade de reagir à elas. Ou também eventos do DOM, como &lt;code class=&quot;language-text&quot;&gt;onLoad&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;O loop dá prioridade à call stack, primeiro ele processa tudo que encontrar na call stack, e só depois que não há nada lá, ele começa a pegar coisas na message queue.&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;Nós não temos que esperar por funções como &lt;code class=&quot;language-text&quot;&gt;setTimeout&lt;/code&gt;, fetch ou outras finalizarem, porque elas são providas pelo browser, elas vivem em suas próprias threads. Por exemplo, se você definir o tempo do &lt;code class=&quot;language-text&quot;&gt;setTimeout&lt;/code&gt; como 2 segundos, você não precisa esperar por 2 segundos - a espera ocorre em outro lugar.&lt;/p&gt;
&lt;h2&gt;ES6 Job Queue&lt;/h2&gt;
&lt;p&gt;O ECMAScript 2015 introduziu o conceito de Job Queue (fila de trabalhos), que é usada por Promises (também introduzidas no ES6/ES2015). É uma maneira de executar o resultado de uma função assíncrona o mais rápido possível, invés de colocar no fim da call stack.&lt;/p&gt;
&lt;p&gt;Promises que são resolvidas antes da função corrente encerrar serão executadas logo após a função corrente.&lt;/p&gt;
&lt;p&gt;Eu acho legal a analogia de uma montanha russa em um parque de diversões: a message queue te coloca no final da fila, antes de todas outras pessoas, onde você terá que esperar pela sua vez, enquanto que a job queue é um ticket corta filas que deixa você ir de novo após a primeira ida.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;iframe
  title=&quot;ECMAScript 2015 Job Queue&quot;
  src=&quot;https://glitch.com/embed/#!/embed/nodejs-dev-0029-03?path=server.js&amp;previewSize=35&amp;attributionHidden=true&amp;sidebarCollapsed=true&quot;
  alt=&quot;nodejs-dev-0029-03 on Glitch&quot;
  style=&quot;height: 400px; width: 100%; border: 0;&quot;&gt;
&lt;/iframe&gt;
&lt;!--```js
const bar = () =&gt; console.log(&apos;bar&apos;)

const baz = () =&gt; console.log(&apos;baz&apos;)

const foo = () =&gt; {
  console.log(&apos;foo&apos;)
  setTimeout(bar, 0)
  new Promise((resolve, reject) =&gt;
    resolve(&apos;should be right after baz, before bar&apos;)
  ).then(resolve =&gt; console.log(resolve))
  baz()
}

foo()
```

Isso imprime

```txt
foo
baz
should be right after baz, before bar
bar
```--&gt;
&lt;p&gt;Há uma grande diferença entre Promises (e Async/await, que é feito com promises) e funções assíncronas antigas como &lt;code class=&quot;language-text&quot;&gt;setTimeout()&lt;/code&gt; ou outras APIs de plataforma.&lt;/p&gt;
&lt;h2&gt;Entendendo o process.nextTick()&lt;/h2&gt;
&lt;p&gt;Uma parte importante do event loop é o &lt;code class=&quot;language-text&quot;&gt;process.nextTick()&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Toda vez que o event loop termina um ciclo, nós chamamos isso de &lt;em&gt;tick&lt;/em&gt;.&lt;/p&gt;
&lt;p&gt;Quando nós passamos uma função pro &lt;code class=&quot;language-text&quot;&gt;process.nextTick()&lt;/code&gt;, nós instruimos a engine a invocar essa função no fim da operação atual, antes que o próximo tick do event loop tenha início.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;nextTick&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;//faça algo&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;O event loop está ocupando processando o código da função atual.&lt;/p&gt;
&lt;p&gt;Quando a operação finaliza, a engine JS executa todas as funções passadas por chamadas do &lt;code class=&quot;language-text&quot;&gt;nextTick&lt;/code&gt; durante aquela operação.&lt;/p&gt;
&lt;p&gt;Esse é o jeito que nós podemos dizer à engine JS para processar uma função assíncronamente (depois da função atual), mas o mais breve possível, sem enfileirar.&lt;/p&gt;
&lt;p&gt;Chamando &lt;code class=&quot;language-text&quot;&gt;setTimeout(() =&amp;gt; {}, 0)&lt;/code&gt; vai executar a função no fim do próximo tick, muito mais tarde do que quando usando &lt;code class=&quot;language-text&quot;&gt;nextTick()&lt;/code&gt;, que prioriza a chamada e a executa antes do próximo tick.&lt;/p&gt;
&lt;p&gt;Use &lt;code class=&quot;language-text&quot;&gt;nextTick()&lt;/code&gt; quando você quer garantir que na próxima iteração do event loop o código já tenha sido executado.&lt;/p&gt;
&lt;h2&gt;Entendendo setImmediate()&lt;/h2&gt;
&lt;p&gt;Quando você quer executar um trecho de código assíncronamente, mas o mais rápido possível, uma opção é utilizar a função &lt;code class=&quot;language-text&quot;&gt;setImmediate()&lt;/code&gt; provida pelo Node.js:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;setImmediate&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;//faça algo&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Qualquer função passada como argumento ao setImmediate() será executada na próxima iteração do event loop.&lt;/p&gt;
&lt;p&gt;Qual a diferença entre &lt;code class=&quot;language-text&quot;&gt;setImmediate()&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;setTimeout(() =&amp;gt; {}, 0)&lt;/code&gt; (passando 0ms como delay), e &lt;code class=&quot;language-text&quot;&gt;process.nextTick()&lt;/code&gt;?&lt;/p&gt;
&lt;p&gt;A função passada para o &lt;code class=&quot;language-text&quot;&gt;process.nextTick()&lt;/code&gt; será executada na iteração atual do event loop, depois que a operação corrente finalizar. Isso significa que ela sempre executa antes do &lt;code class=&quot;language-text&quot;&gt;setTimeout&lt;/code&gt; e do &lt;code class=&quot;language-text&quot;&gt;setImmediate&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Uma callback &lt;code class=&quot;language-text&quot;&gt;setTimeout()&lt;/code&gt; com delay de 0ms é muito similar ao  &lt;code class=&quot;language-text&quot;&gt;setImmediate()&lt;/code&gt;. A ordem de execução vai depender de vários fatores, mas ambas irão rodar na próxima iteração do event loop.&lt;/p&gt;
&lt;h2&gt;Timers do JavaScript&lt;/h2&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;setTimeout()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Quando estiver escrevendo código JavaScript, você pode querer aplicar um delay na execução de uma função.&lt;/p&gt;
&lt;p&gt;Esse é o trabalho da função &lt;code class=&quot;language-text&quot;&gt;setTimeout&lt;/code&gt;. Você especifica uma função de callback para ser executada mais tarde, e um valor em milisegundos especificando o quão mais tarde ela deve rodar:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// roda após 2 segundos&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// roda após 50 milisegundos&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;50&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Essa sintaxe define uma nova função. Você pode chamar qualquer outra função que quiser, ou passar o nome de uma função existente, e definir os parâmetros:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;myFunction&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;firstParam&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; secondParam&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// faz algo&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token comment&quot;&gt;// roda após 2 segundos&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;myFunction&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; firstParam&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; secondParam&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;setTimeout&lt;/code&gt; retorna o código de identificação do timer. Geralmente esse código não é usado, mas você pode guardá-lo, e “limpar” o timer se você quiser desagendar a execução daquela função:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; id &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// deve rodar daqui 2 segundos&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token comment&quot;&gt;// mudei de ideia :v&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;clearTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;id&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;Delay de zero&lt;/h3&gt;
&lt;p&gt;Se você espeficiar o delay do timeout como &lt;code class=&quot;language-text&quot;&gt;0&lt;/code&gt;, a função de callback será executada assim que possível, mas só depois da execução das funções correntes:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;depois &apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos; antes &apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;imprime &lt;code class=&quot;language-text&quot;&gt;antes depois&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Isso é especialmente útil para evitar bloqueio da CPU em tarefas intensas e deixar outras funções serem executadas enquanto são feitos cálculos pesados, enfileirando funções no fluxo.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Alguns browsers (IE e Edge) implementam um método chamado &lt;code class=&quot;language-text&quot;&gt;setImmediate()&lt;/code&gt; que tem a exata mesma funcionalidade, mas não é padronizado e &lt;a href=&quot;https://caniuse.com/#feat=setimmediate&quot;&gt;indisponível em outros navegadores&lt;/a&gt;. Porém é um método padrão no Node.js.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;setInterval()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;setInterval&lt;/code&gt; é uma função similar ao &lt;code class=&quot;language-text&quot;&gt;setTimeout&lt;/code&gt;, mas com uma diferença: em vez de rodar a função de callback uma vez, ela será rodada pra sempre, a cada intervalo de tempo especificado (em milisegundos):&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;setInterval&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// roda a cada 2 segundos&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;A função abaixo roda a cada 2 segundos até que você a diga pra parar, usando &lt;code class=&quot;language-text&quot;&gt;clearInterval&lt;/code&gt;, passando o identificador retornado por aquele &lt;code class=&quot;language-text&quot;&gt;setInterval&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; id &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;setInterval&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// roda a cada 2 segundos&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token function&quot;&gt;clearInterval&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;id&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;É comum chamar o &lt;code class=&quot;language-text&quot;&gt;clearInterval&lt;/code&gt; dentro da função de callback do setInterval, para auto-determinar se ele deve rodar de novo ou parar. Por exemplo, esse código roda algo a não ser que o valor de App.somethingIWait seja &lt;code class=&quot;language-text&quot;&gt;arrived&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; interval &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;setInterval&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;App&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;somethingIWait &lt;span class=&quot;token operator&quot;&gt;===&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;arrived&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token function&quot;&gt;clearInterval&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;interval&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// caso contrário, executa o conteúdo restante&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;100&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;setTimeout recursivo&lt;/h2&gt;
&lt;p&gt;O &lt;code class=&quot;language-text&quot;&gt;setInterval&lt;/code&gt; inicia uma função a cada n milisegundos, sem levar em consideração quando uma função finalizou sua execução.&lt;/p&gt;
&lt;p&gt;Se uma função gasta sempre o mesmo espaço de tempo, show de bola:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/fa9e9fec1aea517d98b47b11c5fec296/ca682/setinterval-ok.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 14.560669456066943%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAADCAIAAAAcOLh5AAAACXBIWXMAAAsSAAALEgHS3X78AAAAh0lEQVQI102MuQrCQBCG8/4PIdjYWoiNIAiCdgmIKILgupDGybG498ws0SiE/br/LIaMGAJ5lzvGamaeZGIOxk+yyKsu4ra2K2lvXfg7unVwN62wGMaLlNK+ua6bqlSPcYwR4w9CVNouLjA7w0H2wzdgAqlE+ZIneHeGiZz3y+dxLnabukLEDzLVqiZANHp3AAAAAElFTkSuQmCC&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;setInterval funcionando belezinha&quot;
        title=&quot;setInterval funcionando belezinha&quot;
        src=&quot;/static/fa9e9fec1aea517d98b47b11c5fec296/799d3/setinterval-ok.png&quot;
        srcset=&quot;/static/fa9e9fec1aea517d98b47b11c5fec296/00d96/setinterval-ok.png 148w,
/static/fa9e9fec1aea517d98b47b11c5fec296/0b23c/setinterval-ok.png 295w,
/static/fa9e9fec1aea517d98b47b11c5fec296/799d3/setinterval-ok.png 590w,
/static/fa9e9fec1aea517d98b47b11c5fec296/2a3d6/setinterval-ok.png 885w,
/static/fa9e9fec1aea517d98b47b11c5fec296/ae92f/setinterval-ok.png 1180w,
/static/fa9e9fec1aea517d98b47b11c5fec296/ca682/setinterval-ok.png 1195w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Talvez a função gaste tempos diferentes de execução, dependendo das condições da internet por exemplo:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/f2ae544ad5038515ba1d44b29322bec9/6d707/setinterval-varying-duration.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 14.357682619647354%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAADCAIAAAAcOLh5AAAACXBIWXMAAAsSAAALEgHS3X78AAAAlUlEQVQI102IvQ6CMBgAeXoHZ42Ju4tPoIkmqIMsGjBRpxaJikZoq9AfPgqtPzGEyy13jm1RaQ0ybx8uOJTQpLFWZcLW/3Sa+wF0PTvzZSzcr8pYIzOgqCCRZBdBT/KJYXNHLj246T7IIgd+FABVCYyrzpYMg8dgl3Z9pgrJbjmev0IvifwEr8l1kY+Oq1446aPpOPbejmulxpnqolgAAAAASUVORK5CYII=&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;setInterval variando de duração&quot;
        title=&quot;setInterval variando de duração&quot;
        src=&quot;/static/f2ae544ad5038515ba1d44b29322bec9/799d3/setinterval-varying-duration.png&quot;
        srcset=&quot;/static/f2ae544ad5038515ba1d44b29322bec9/00d96/setinterval-varying-duration.png 148w,
/static/f2ae544ad5038515ba1d44b29322bec9/0b23c/setinterval-varying-duration.png 295w,
/static/f2ae544ad5038515ba1d44b29322bec9/799d3/setinterval-varying-duration.png 590w,
/static/f2ae544ad5038515ba1d44b29322bec9/2a3d6/setinterval-varying-duration.png 885w,
/static/f2ae544ad5038515ba1d44b29322bec9/ae92f/setinterval-varying-duration.png 1180w,
/static/f2ae544ad5038515ba1d44b29322bec9/6d707/setinterval-varying-duration.png 1191w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;E talvez uma longa execução sobreponha a próxima:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/4e64c07dfb9f7be0e819fe3eb7def66a/cb5f6/setinterval-overlapping.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 14.201680672268907%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAADCAIAAAAcOLh5AAAACXBIWXMAAAsSAAALEgHS3X78AAAAqElEQVQI102NQQ7BQBiFeypHcAAnkDiChdhbiDs4ikRogqRBa6VESmi1UzNm/umM+atFNBLf5r3ke8mzXn8gYkxSZZBpvGnMTB5Tlkj4qPK3ASmeRV51q4rKqbxoTKE2Uk2btRe0PobWRDiOSLea7DNykOlOXX2gZ/m5KcrSMl8exiAaULrv8s4Sei4feLy7EsP1PZmJwBaBQ46b+DRnvheFlzCMIgr8DaD2ooqPp9kcAAAAAElFTkSuQmCC&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;setInterval sobrepondo execuções&quot;
        title=&quot;setInterval sobrepondo execuções&quot;
        src=&quot;/static/4e64c07dfb9f7be0e819fe3eb7def66a/799d3/setinterval-overlapping.png&quot;
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        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Para evitar isso, você pode agendar um setTimout recursivo para ser chamado quando a função de callback finaliza:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;myFunction&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// faz algo&lt;/span&gt;

  &lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;myFunction&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;1000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;myFunction&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;1000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Pra chegar nesse cenário:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/4bde07363650160e953f899734adc29e/46247/recursive-settimeout.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 14.297729184188393%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAADCAIAAAAcOLh5AAAACXBIWXMAAAsSAAALEgHS3X78AAAAhUlEQVQI102MSw7CMAxEc/9LsOAOiAVXAKmCJVBAXbRKFIXGTp0vOM2mb+PxeDzityGGQGhZlFKaAwBEtM18jUkpNS3aaFmK6fSeDx/spKsFpfBnzrm2aJIPUE8A43hlk6/Cr5D3MXiDy/467m7yeJcOKlprO1tccOxVf55eFzkNCh3alT9xxqv3UrGNyQAAAABJRU5ErkJggg==&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;setTimeout recursivo&quot;
        title=&quot;setTimeout recursivo&quot;
        src=&quot;/static/4bde07363650160e953f899734adc29e/799d3/recursive-settimeout.png&quot;
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/static/4bde07363650160e953f899734adc29e/ae92f/recursive-settimeout.png 1180w,
/static/4bde07363650160e953f899734adc29e/46247/recursive-settimeout.png 1189w&quot;
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        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;setTimeout&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;setInterval&lt;/code&gt; estão disponívels no Node.js, através do &lt;a href=&quot;https://nodejs.org/api/timers.html&quot;&gt;módulo Timers&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;O Node.js também disponibiliza o &lt;code class=&quot;language-text&quot;&gt;setImmediate()&lt;/code&gt;, que é o equivalente de usar &lt;code class=&quot;language-text&quot;&gt;setTimeout(() =&amp;gt; {}, 0)&lt;/code&gt;, normalmente utilizado para trabalhar com o Event Loop do Node.js.&lt;/p&gt;
&lt;h2&gt;Programação Assincrona e Callbacks&lt;/h2&gt;
&lt;h2&gt;Assincronicidade em Linguagens de Programação&lt;/h2&gt;
&lt;p&gt;Computadores são assíncronos por definição.&lt;/p&gt;
&lt;p&gt;Assíncrono significa que as coisas podem acontecer independemente do fluxo principal do programa.&lt;/p&gt;
&lt;p&gt;Nos computadores de uso doméstico  atuais, cada programa roda por um intervalo de tempo específico e, em seguida, interrompe sua execução para permitir que outro programa continue sua execução. Isso roda em um ciclo tão rápido que é impossível de notar. Nós pensamos que nossos computadores rodam diversos programass simultaneamente, mas isso é uma ilusão (exceto em máquinas multiprocessadas).&lt;/p&gt;
&lt;p&gt;Programas usam internamente &lt;em&gt;sinais de interrupção (interrupts)&lt;/em&gt;, que são emitidos ao processador para ganharem a atenção do sistema.&lt;/p&gt;
&lt;p&gt;Não irei muito a fundo no conceito, mas só tenha em mente que é normal para programas serem assíncronos e pararem a execução até que precisem de atenção, permitindo ao computador executar outras coisas nesse meio tempo. Quando um programa está esperando por uma resposta da rede, ele não pode parar o processador até que a requisição finalize.&lt;/p&gt;
&lt;p&gt;Normalmente, linguagens de programação são síncronas e algumas fornecem maneiras de gerenciar assincronicidade na própria linguagem ou por meio de bibliotecas. C, Java, C#, PHP, Go, Ruby, Swift, e Python são todas síncronas por padrão. Algumas delas gerenciam assíncronismo usando threads, gerando um novo processo.&lt;/p&gt;
&lt;h2&gt;JavaScript&lt;/h2&gt;
&lt;p&gt;JavaScript é &lt;strong&gt;síncrono&lt;/strong&gt; por padrão e roda em uma única thread. Isso significa que o código não pode criar novas threads e rodar em paralelo.&lt;/p&gt;
&lt;p&gt;Linhas de código são executadas em séries, uma após a outra, por exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; a &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; b &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; c &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; a &lt;span class=&quot;token operator&quot;&gt;*&lt;/span&gt; b
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;c&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;doSomething&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Mas o JavaScript nasceu dentro dos browsers, sua função principal, desde o começo, era responder às interações do usuário, como &lt;code class=&quot;language-text&quot;&gt;onClick&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;onMouseOver&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;onChange&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;onSubmit&lt;/code&gt; e etc. Como isso pode ser feito com um modelo programático síncrono?&lt;/p&gt;
&lt;p&gt;A resposta era o ambiente. O &lt;strong&gt;browser&lt;/strong&gt; dá um jeito nisso fornecendo um conjunto de APIs que podem lidar com esses tipos de funcionalidades.&lt;/p&gt;
&lt;p&gt;Mais recentemente, o Node.js introduziu um ambiente de I/O não bloqueante para estender esse conceito a acesso de arquivos, chamadas de rede e etc.&lt;/p&gt;
&lt;h2&gt;Callbacks&lt;/h2&gt;
&lt;p&gt;Não tem como você saber quando um usuário vai clicar em um botão. Então, você &lt;strong&gt;define uma função para lidar com o evento de click&lt;/strong&gt;. Essa função será chamada quando o evento for acionado:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;document&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;getElementById&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;button&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;addEventListener&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;click&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// item clicado&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso também é chamado de &lt;strong&gt;callback&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Uma callback é uma simples função que é passada como valor para outra função, e só será executada quando o evento ocorrer. Nós podemos fazer isso por que o JavaScript têm funções de “primeira classe”, que podem ser atribuidas à variáveis e passadas para outras funções chamadas de &lt;strong&gt;higher-order functions (funções de ordem superior)&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;É comum envolver todo código do cliente em um event listener do tipo &lt;code class=&quot;language-text&quot;&gt;load&lt;/code&gt; no objeto &lt;code class=&quot;language-text&quot;&gt;window&lt;/code&gt;, que roda só roda a função callback quando a página está pronta:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;window&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;addEventListener&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;load&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// window carregou&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// faça o que quiser&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Callbacks são usadas em todo lugar, não só em eventos do DOM.&lt;/p&gt;
&lt;p&gt;Um exemplo comum é utilizando temporizadores:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// roda após 2 segundos&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Requisições XHR também aceitam uma callback, nesse exemplo ao passar uma função para uma propriedade que será chamada quando um evento em particular ocorrer (nesse caso, o estado da requisição mudar):&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; xhr &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;XMLHttpRequest&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
xhr&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function-variable function&quot;&gt;onreadystatechange&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;xhr&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;readyState &lt;span class=&quot;token operator&quot;&gt;===&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;4&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    xhr&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;status &lt;span class=&quot;token operator&quot;&gt;===&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;200&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;?&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;xhr&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;responseText&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
xhr&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;open&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;GET&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;https://yoursite.com&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
xhr&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;send&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Tratando erros em callbacks&lt;/h2&gt;
&lt;p&gt;Como você trata erros em callbacks? Uma estratégia muito comum é usar o que o Node.js adotou: o primeiro parâmetro em qualquer função callback é o objeto de erro: &lt;strong&gt;error-first callbacks&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;Se não há erro, o objeto é nulo (&lt;code class=&quot;language-text&quot;&gt;null&lt;/code&gt;). Se há um erro, ele contêm alguma descrição do erro e outras informações.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;readFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/file.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; data&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err &lt;span class=&quot;token operator&quot;&gt;!==&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;null&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token comment&quot;&gt;// tratando erro&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

  &lt;span class=&quot;token comment&quot;&gt;// sem erros, processe o data&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;O problema com callbacks&lt;/h2&gt;
&lt;p&gt;Callbacks são ótimas para casos simples!&lt;/p&gt;
&lt;p&gt;Entretanto, toda callback adiciona um nível de aninhamento, e quando você têm muitas callbacks, o código começa a se complicar rapidamente:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;window&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;addEventListener&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;load&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  document&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;getElementById&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;button&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;addEventListener&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;click&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      items&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;forEach&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;item&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
        &lt;span class=&quot;token comment&quot;&gt;// seu código aqui&lt;/span&gt;
      &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Esse é só um exemplo simples com 4 níveis de aninhamento, mas eu já vi códigos com muito mais níveis e não é nem um pouco divertido.&lt;/p&gt;
&lt;p&gt;Como resolver isso?&lt;/p&gt;
&lt;h2&gt;Alternativas à callbacks&lt;/h2&gt;
&lt;p&gt;A partir do ES6, o JavaScript introduziu várias funcionalidades que nos ajudam a lidar com código assíncrono sem o uso de callbacks: Promises (ES6) e Async/Await (ES2017).&lt;/p&gt;
&lt;h2&gt;Promises no JavaScript&lt;/h2&gt;
&lt;h2&gt;Introdução a Promises&lt;/h2&gt;
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&lt;p&gt;Uma promise (promessa) é comumente definida como &lt;strong&gt;um proxy para um valor que eventualmente ficará disponível&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Promises são um jeito de lidar com código assíncrono, sem ficar preso em &lt;a href=&quot;http://callbackhell.com/&quot;&gt;“inferno de callbacks” (callback hell)&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Promises são parte da linguagem por anos (introduzidas e padronizadas no ES2015), e se tornaram mais integradas recentemente, com &lt;strong&gt;async&lt;/strong&gt; e &lt;strong&gt;await&lt;/strong&gt; no ES2017.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Funções async&lt;/strong&gt; usam promises por baixo dos panos, então entender como promises funcionam é fundamental para entender como &lt;strong&gt;async&lt;/strong&gt; e &lt;strong&gt;await&lt;/strong&gt; funcionam.&lt;/p&gt;
&lt;h3&gt;Como promises funcionam, resumidamente&lt;/h3&gt;
&lt;p&gt;Uma vez que a promise tenha sido chamada, ela inicia em um &lt;strong&gt;estado pendente (pending)&lt;/strong&gt;. Isso significa que a função que a chamou continua executando, enquanto a promise estiver pendente até que se resolva, retornando à função que a invocou os dados que foram requisitados.&lt;/p&gt;
&lt;p&gt;A promise criada vai eventualmente se encerrar em um &lt;strong&gt;estado resolvido (resolved)&lt;/strong&gt;, ou em um &lt;strong&gt;estado rejeitado (rejected)&lt;/strong&gt;, chamando as respectivas funções callback (&lt;code class=&quot;language-text&quot;&gt;then&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;catch&lt;/code&gt;) ao terminar.&lt;/p&gt;
&lt;h3&gt;Quais APIs JS usam promises?&lt;/h3&gt;
&lt;p&gt;Em adição ao seu código e o de bibliotecas, promises são usadas por padrão em APIs web modernas, como:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Battery API&lt;/li&gt;
&lt;li&gt;Fetch API&lt;/li&gt;
&lt;li&gt;Service Workers&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;É improvável que você mesmo &lt;em&gt;não&lt;/em&gt; esteja utilizando promises no JavaScript moderno, então vamos começar a mergulhar nelas.&lt;/p&gt;
&lt;hr&gt;
&lt;h2&gt;Criando uma promise&lt;/h2&gt;
&lt;p&gt;A Promise API expõe um contrutor Promise, por onde você inicializa usando &lt;code class=&quot;language-text&quot;&gt;new Promise()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;let&lt;/span&gt; done &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; isItDoneYet &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Promise&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;resolve&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;done&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; workDone &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Here is the thing I built&apos;&lt;/span&gt;
    &lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;workDone&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;else&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; why &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Still working on something else&apos;&lt;/span&gt;
    &lt;span class=&quot;token function&quot;&gt;reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;why&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Como você pode ver, a promise checa a constante global &lt;code class=&quot;language-text&quot;&gt;done&lt;/code&gt;, e se for true, a promise vai para o estado &lt;strong&gt;resolved&lt;/strong&gt; (uma vez que a callback &lt;code class=&quot;language-text&quot;&gt;resolve&lt;/code&gt; tenha sido chamada); caso contrário, a callback &lt;code class=&quot;language-text&quot;&gt;reject&lt;/code&gt; é executada, colocando a promise em um estado &lt;strong&gt;rejected&lt;/strong&gt;. (Se nenhuma dessas funções é chamada, a promise permanece no estado &lt;strong&gt;pending&lt;/strong&gt;).&lt;/p&gt;
&lt;p&gt;Usando &lt;code class=&quot;language-text&quot;&gt;resolve&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;reject&lt;/code&gt;, podemos nos comunicar com a função invocadora dizendo qual estado a promise estava, e o que fazer com isso. No caso acima nós só retornamos uma string, mas poderia ser um objeto, ou mesmo &lt;code class=&quot;language-text&quot;&gt;null&lt;/code&gt;. Só de termos criado a promise no trecho acima, ela já começou a executar. É importante entender o que está acontecendo na seção &lt;a href=&quot;#consumindo-uma-promise&quot;&gt;Consumindo uma promise&lt;/a&gt; logo abaixo.&lt;/p&gt;
&lt;p&gt;Um exemplo mais comum que você pode encontrar por aí é uma técnica chamada &lt;strong&gt;Promisifying (promissificar)&lt;/strong&gt;. Essa técnica é um jeito de poder usar uma função JavaScript clássica que recebe uma callback, e retornar uma promise:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;getFile&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;fileName&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Promise&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;resolve&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;readFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;fileName&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; data&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
        &lt;span class=&quot;token function&quot;&gt;reject&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;  &lt;span class=&quot;token comment&quot;&gt;// chamar `reject` vai fazer com  que a promise falhe com ou sem o erro passado como argumento&lt;/span&gt;
        &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt;        &lt;span class=&quot;token comment&quot;&gt;// e não queremos ir mais longe&lt;/span&gt;
      &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
      &lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token function&quot;&gt;getFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/etc/passwd&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;data&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;blockquote&gt;
&lt;p&gt;Em versões recentes do Node.js, você não precisa fazer essa conversão manual para grande parte da API. Há uma função promisifying disponível no &lt;a href=&quot;https://nodejs.org/docs/latest-v11.x/api/util.html#util_util_promisify_original&quot;&gt;módulo util&lt;/a&gt; que fará isso por você, dado que a função que você esteja “promissificando” siga a assinatura correta.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;hr&gt;
&lt;h2&gt;Consumindo uma promise&lt;/h2&gt;
&lt;p&gt;Na última seção, nós introduzimos como uma promise é criada.&lt;/p&gt;
&lt;p&gt;Agora vamos ver como uma promise pode ser &lt;em&gt;consumida&lt;/em&gt; ou usada.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; isItDoneYet &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Promise&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token comment&quot;&gt;/* ... como acima ... */&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token comment&quot;&gt;//...&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;checkIfItsDone&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  isItDoneYet
    &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;ok&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;ok&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Rodar &lt;code class=&quot;language-text&quot;&gt;checkIfItsDone()&lt;/code&gt; vai especificar funções para executar quando a promise &lt;code class=&quot;language-text&quot;&gt;isItDoneYet&lt;/code&gt; resolver (na chamada &lt;code class=&quot;language-text&quot;&gt;then&lt;/code&gt;) ou rejeitar (na chamada &lt;code class=&quot;language-text&quot;&gt;catch&lt;/code&gt;).&lt;/p&gt;
&lt;hr&gt;
&lt;h2&gt;Encadeando promises&lt;/h2&gt;
&lt;p&gt;Uma promise pode ser retornada para outra promise, criando uma cadeia de promises.&lt;/p&gt;
&lt;p&gt;Um ótimo exemplo de encadeamento de promises é a Fetch API, que podemos usar para obter um recurso e enfileirar uma cadeia de promises para executar quando o recurso for obtido.&lt;/p&gt;
&lt;p&gt;A Fetch API um mecanismo baseado em promise, e chamar &lt;code class=&quot;language-text&quot;&gt;fetch()&lt;/code&gt; é equivalente a definir suas próprias promises usando &lt;code class=&quot;language-text&quot;&gt;new Promise()&lt;/code&gt;.&lt;/p&gt;
&lt;h3&gt;Exemplo de encadeamento de promises&lt;/h3&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;status&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;response&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;response&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;status &lt;span class=&quot;token operator&quot;&gt;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;200&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;&amp;amp;&amp;amp;&lt;/span&gt; response&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;status &lt;span class=&quot;token operator&quot;&gt;&amp;lt;&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;300&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; Promise&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;response&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; Promise&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;response&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusText&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;json&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;response&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; response&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;json&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token function&quot;&gt;fetch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/todos.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;status&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;    &lt;span class=&quot;token comment&quot;&gt;// note que a função `status` é na verdade **chamada** aqui, e ela **retorna uma promise**&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;json&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;      &lt;span class=&quot;token comment&quot;&gt;// da mesma forma, a única diferença aqui é que a função `json` retorna uma promise que é resolvida com `data`&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;data&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;  &lt;span class=&quot;token comment&quot;&gt;// ... por isso que `data` aparece aqui como primeiro parâmetro da função anônima&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Request succeeded with JSON response&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;error&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Request failed&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; error&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Nesse exemplo, nós chamamos &lt;code class=&quot;language-text&quot;&gt;fetch()&lt;/code&gt; para obter uma lita de items TODO do arquivo &lt;code class=&quot;language-text&quot;&gt;todos.json&lt;/code&gt; localizado na raiz do domínio, e nós criamos uma cadeia de promises.&lt;/p&gt;
&lt;p&gt;Rodanr &lt;code class=&quot;language-text&quot;&gt;fetch()&lt;/code&gt; retorna uma &lt;a href=&quot;https://fetch.spec.whatwg.org/#concept-response&quot;&gt;response (resposta)&lt;/a&gt;, que contém várias propriedades, e dentre elas as que usamos no exemplo:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;status&lt;/code&gt;, um valor numérico representando o código de status HTTP&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;statusText&lt;/code&gt;, uma mensagem de status, que será &lt;code class=&quot;language-text&quot;&gt;OK&lt;/code&gt; se a requisição for bem-sucedida.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;response&lt;/code&gt; também tem um método &lt;code class=&quot;language-text&quot;&gt;json()&lt;/code&gt;, que retorna uma promise que vai resolver com o conteúdo do body processado e transformado em JSON.&lt;/p&gt;
&lt;p&gt;Então dadas essas promises, isso é o que acontece: a primeira promise na cadeia é a função que nós definimos, chamada &lt;code class=&quot;language-text&quot;&gt;status()&lt;/code&gt;, que checa o status da response e se não for uma resposta bem-sucedida (entre 200 e 299), a promise é rejeitada.&lt;/p&gt;
&lt;p&gt;Essa operação fará com que a cadeia de promises pule todas promises encadeadas e pule diretamente para o &lt;code class=&quot;language-text&quot;&gt;catch()&lt;/code&gt; no final, logando o texto &lt;code class=&quot;language-text&quot;&gt;Request failed&lt;/code&gt; e a mensagem de erro.&lt;/p&gt;
&lt;p&gt;Se em vez disso obter suceddo, é chamada a função &lt;code class=&quot;language-text&quot;&gt;json()&lt;/code&gt; que definimos. Desde que a promise anterior, quando bem-sucedida, tenha retornado o objeto &lt;code class=&quot;language-text&quot;&gt;response&lt;/code&gt;, nós o obtemos como um input para a segunda promise.&lt;/p&gt;
&lt;p&gt;Nesse caso, nós retornamos os dados processados em JSON, assim a terceira promise recebe o JSON diretamente:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;data&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Request succeeded with JSON response&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e nós simplesmente o logamos no console.&lt;/p&gt;
&lt;hr&gt;
&lt;h2&gt;Tratando erros&lt;/h2&gt;
&lt;p&gt;No exemplo da seção anterior, nós tinhamos um &lt;code class=&quot;language-text&quot;&gt;catch&lt;/code&gt; que foi adicionado na cadeia de promises.&lt;/p&gt;
&lt;p&gt;Quando qualquer coisa na cadeia de promises falha e dispara um erro ou rejeita uma promise, o controle vai para o &lt;code class=&quot;language-text&quot;&gt;catch()&lt;/code&gt; mais próximo na cadeia.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Promise&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;resolve&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;throw&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token comment&quot;&gt;// or&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Promise&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;resolve&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;Cascateando erros&lt;/h3&gt;
&lt;p&gt;Se dentro do &lt;code class=&quot;language-text&quot;&gt;catch()&lt;/code&gt; você lançar um erro, você pode adicionar um segundo &lt;code class=&quot;language-text&quot;&gt;catch()&lt;/code&gt; para tratá-lo, e assim por diante.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Promise&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;resolve&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;throw&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;throw&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;hr&gt;
&lt;h2&gt;Orquestrando promises&lt;/h2&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;Promise.all()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Se você precisa sincronizar promises diferentes, &lt;code class=&quot;language-text&quot;&gt;Promise.all()&lt;/code&gt; te ajuda a definir uma lista de promises, e executa algo quando elas todas são resolvidas.&lt;/p&gt;
&lt;p&gt;Examplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; f1 &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;fetch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/something.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; f2 &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;fetch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/something2.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

Promise&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;all&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;f1&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; f2&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;res&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Array of results&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;A sintaxe de atribuição por desestruturação do ES2015 permite que você também faça isso:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;Promise&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;all&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;f1&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; f2&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;res1&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res2&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Results&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res1&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res2&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;É claro que você não está limitado a só usar o &lt;code class=&quot;language-text&quot;&gt;fetch&lt;/code&gt;, &lt;strong&gt;qualquer promise pode ser usada dessa forma&lt;/strong&gt;.&lt;/p&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;Promise.race()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;Promise.race()&lt;/code&gt; roda quando a primeira das promises que você passar for resolvida, e roda a callback anexada apenas uma vez, com o resultado da primeira promise resolvida.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; first &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Promise&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;resolve&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;resolve&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;500&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;first&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; second &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Promise&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;resolve&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; reject&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;resolve&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;100&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;second&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

Promise&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;race&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;first&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; second&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;result&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;result&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// second&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Erros comuns&lt;/h2&gt;
&lt;h3&gt;Uncaught TypeError: undefined is not a promise&lt;/h3&gt;
&lt;p&gt;Se você obter um erro &lt;code class=&quot;language-text&quot;&gt;Uncaught TypeError: undefined is not a promise&lt;/code&gt; no console, certifique-se de usar &lt;code class=&quot;language-text&quot;&gt;new Promise()&lt;/code&gt; em vez de apenas &lt;code class=&quot;language-text&quot;&gt;Promise()&lt;/code&gt;.&lt;/p&gt;
&lt;h3&gt;UnhandledPromiseRejectionWarning&lt;/h3&gt;
&lt;p&gt;Isso significa que a promise que você chamou foi rejeitada, mas não tinha nenhum &lt;code class=&quot;language-text&quot;&gt;catch&lt;/code&gt; preparado para tratar o erro. Adicione um &lt;code class=&quot;language-text&quot;&gt;catch&lt;/code&gt; depois do &lt;code class=&quot;language-text&quot;&gt;then&lt;/code&gt; causador do erro para tratá-lo propriamente.&lt;/p&gt;
&lt;h2&gt;Programação assincrona moderna com Async Await no Javascript&lt;/h2&gt;
&lt;h2&gt;Introdução&lt;/h2&gt;
&lt;p&gt;O JavaScript evoluiu de callbacks para promises (ES2015) em um curto período de tempo, e desde o ES2017, JavaScript assíncrono está ainda mais simples com a sintaxe async/await.&lt;/p&gt;
&lt;p&gt;Funções async são uma combinação de promises e generators, e basicamente, elas são uma abstração de alto nível das promises. Permita-me repetir: &lt;strong&gt;async/await é feito com promises&lt;/strong&gt;.&lt;/p&gt;
&lt;h2&gt;Por que a sintaxe async/await foi criada?&lt;/h2&gt;
&lt;p&gt;Ela reduz o amontoado de código em torno das prommises e a limitação de “não quebre a corrente” das promises encadeadas.&lt;/p&gt;
&lt;p&gt;Quando as Promises foram introduzidas no ES2016, elas foram feitas para resolver um problema com código assíncrono, e elas fizeram isso, mas ao longos dos 2 anos que separaram o ES2015 do ES2017, ficou claro que &lt;em&gt;promises poderiam não ser a solução definitiva&lt;/em&gt;.&lt;/p&gt;
&lt;p&gt;Promises foram introduzidas para resolver o famoso problema de &lt;em&gt;callback hell&lt;/em&gt;, mas elas introduziram complexidade por si só, e complexidade sintática.&lt;/p&gt;
&lt;p&gt;Elas foram boas primitivas enquanto uma sintaxe melhor não surgia, então, quando chegou a hora certa, obtivemos as &lt;strong&gt;funções async&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Elas fazem o código parecer síncrono, mas por baixo dos panos ele é assíncrono e não bloqueante.&lt;/p&gt;
&lt;h2&gt;Como isso funciona&lt;/h2&gt;
&lt;p&gt;Uma função async retorna uma promise, como nesse exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;doSomethingAsync&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Promise&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;resolve&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token function&quot;&gt;setTimeout&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;I did something&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;3000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Quando você quer &lt;strong&gt;chamar&lt;/strong&gt; essa função você prexifa um &lt;code class=&quot;language-text&quot;&gt;await&lt;/code&gt;, e &lt;strong&gt;o código corrente vai parar até que a promise seja resolvida ou rejeitada&lt;/strong&gt;. Uma ressalva: a função deve ser definida como &lt;code class=&quot;language-text&quot;&gt;async&lt;/code&gt;. Segue um exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;doSomething&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;async&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token keyword&quot;&gt;await&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;doSomethingAsync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Um exemplo rápido&lt;/h2&gt;
&lt;p&gt;Esse é um exemplo bem simples de async/await sendo usado para rodar uma função assíncronamente:&lt;/p&gt;
&lt;iframe
  title=&quot;Modern Asynchronous JavaScript with Async and Await&quot;
  src=&quot;https://glitch.com/embed/#!/embed/nodejs-dev-0035-01?path=server.js&amp;previewSize=25&amp;attributionHidden=true&amp;sidebarCollapsed=true&quot;
  alt=&quot;nodejs-dev-0035-01 on Glitch&quot;
  style=&quot;height: 400px; width: 100%; border: 0;&quot;&gt;
&lt;/iframe&gt;
&lt;!--```js
const doSomethingAsync = () =&gt; {
  return new Promise(resolve =&gt; {
    setTimeout(() =&gt; resolve(&apos;I did something&apos;), 3000)
  })
}

const doSomething = async () =&gt; {
  console.log(await doSomethingAsync())
}

console.log(&apos;Before&apos;)
doSomething()
console.log(&apos;After&apos;)
```

O código acima imrprimirá o seguinte no console do browser:

```
Before
After
I did something // depois de 3s
```--&gt;
&lt;h2&gt;“Promissifique” tudo&lt;/h2&gt;
&lt;p&gt;Prefixar o termo &lt;code class=&quot;language-text&quot;&gt;async&lt;/code&gt; em qualquer função implica que a função vai retornar uma promise.&lt;/p&gt;
&lt;p&gt;Mesmo que isso não seja feito tão explicitamente, internamente fará com que retorne uma promise.&lt;/p&gt;
&lt;p&gt;Por isso que esse código é válido:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;aFunction&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;async&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;test&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token function&quot;&gt;aFunction&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;alert&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// Isso vai invocar um alert com o texto &apos;test&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e o mesmo aqui:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;aFunction&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;async&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; Promise&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;test&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token function&quot;&gt;aFunction&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;alert&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// Isso vai invocar um alert com o texto &apos;test&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;O código é muito mais simples de ler&lt;/h2&gt;
&lt;p&gt;Como você pôde ver no exemplo acima, nosso código parece muito simples. Compare-o com os códigos usando promises simples, encadeamento e funções callback.&lt;/p&gt;
&lt;p&gt;E esse é um exemplo bem simples, os maiores benefícios vão aparecer quando o código for mais complexo.&lt;/p&gt;
&lt;p&gt;Por exemplo, aqui temos um código de como obter um recurso JSON e “parsear”, usando promises:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;getFirstUserData&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;fetch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/users.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// pega a lista de users&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;response&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; response&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;json&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// parse JSON&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;users&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; users&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// pega o primeiro usuário&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;user&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;fetch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;/users/&lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;user&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;name&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// pega os dados desse usuário&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;userResponse&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; userResponse&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;json&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// parse JSON&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token function&quot;&gt;getFirstUserData&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;E aqui temos a mesma funcionalidade usando async/await:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;getFirstUserData&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;async&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; response &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;await&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;fetch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/users.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// pega a lista de users&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; users &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;await&lt;/span&gt; response&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;json&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// parse JSON&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; user &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; users&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// pega o primeiro usuário&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; userResponse &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;await&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;fetch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;/users/&lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;user&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;name&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// pega os dados desse usuário&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; userData &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;await&lt;/span&gt; userResponse&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;json&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// parse JSON&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; userData
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token function&quot;&gt;getFirstUserData&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Múltiplas funções async em série&lt;/h2&gt;
&lt;p&gt;Funções async podem ser encadeadas facilmente, e a sintaxe é muito mais legível do que usando promises simples:&lt;/p&gt;
&lt;iframe
  title=&quot;Multiple async functions in series&quot;
  src=&quot;https://glitch.com/embed/#!/embed/nodejs-dev-0035-02?path=server.js&amp;previewSize=30&amp;attributionHidden=true&amp;sidebarCollapsed=true&quot;
  alt=&quot;nodejs-dev-0035-02 on Glitch&quot;
  style=&quot;height: 400px; width: 100%; border: 0;&quot;&gt;
&lt;/iframe&gt;
&lt;!--```js
const promiseToDoSomething = () =&gt; {
  return new Promise(resolve =&gt; {
    setTimeout(() =&gt; resolve(&apos;I did something&apos;), 10000)
  })
}

const watchOverSomeoneDoingSomething = async () =&gt; {
  const something = await promiseToDoSomething()
  return something + &apos; and I watched&apos;
}

const watchOverSomeoneWatchingSomeoneDoingSomething = async () =&gt; {
  const something = await watchOverSomeoneDoingSomething()
  return something + &apos; and I watched as well&apos;
}

watchOverSomeoneWatchingSomeoneDoingSomething().then(res =&gt; {
  console.log(res)
})
```

Vai imprimir:

```
I did something and I watched and I watched as well
```--&gt;
&lt;h2&gt;Mais fácil de debugar&lt;/h2&gt;
&lt;p&gt;É difícil debugar promises porque o debugger não passa por cima de código assíncrono.&lt;/p&gt;
&lt;p&gt;Já Async/await facilita muito isso porque para o compilador é como se fosse apenas código síncrono.&lt;/p&gt;
&lt;h2&gt;O Event emitter&lt;/h2&gt;
&lt;p&gt;Se você já trabalhou com JavaScript no browser, já sabe o quão grande é a quantidade de ações do usuário que são tratadas por eventos: clicks do mouse, teclas sendo pressionadas, movimentos do mouse, e muito mais.&lt;/p&gt;
&lt;p&gt;No lado do backend, o Node.js nos oferece a opção de trabalhar com um sitema similar usando o &lt;a href=&quot;https://nodejs.org/api/events.html&quot;&gt;módulo &lt;code class=&quot;language-text&quot;&gt;events&lt;/code&gt;&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Esse módulo, em particular, fornece a classe &lt;code class=&quot;language-text&quot;&gt;EventEmitter&lt;/code&gt;, que nós utilizaremos para lidar com nossos eventos.&lt;/p&gt;
&lt;p&gt;Você a inicializa usando&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; EventEmitter &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;events&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; eventEmitter &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;EventEmitter&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Esse objeto expõe, entre muitos outros, os métodos &lt;code class=&quot;language-text&quot;&gt;on&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;emit&lt;/code&gt;.&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;emit&lt;/code&gt; é usado para acionar um evento&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;on&lt;/code&gt; é usado para adicionar uma função callback que será executada quando o evento for acionado&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Por exemplo, vamos criar um evento &lt;code class=&quot;language-text&quot;&gt;start&lt;/code&gt;, e para dar uma amostra grátis, vamos reagir a ele logando no console:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;eventEmitter&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;start&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;started&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Quando rodamos&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;eventEmitter&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;emit&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;start&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;a função que lida com o evento é acionada, e obtemos o log.&lt;/p&gt;
&lt;p&gt;Você pode passar argumentos à função passando-os como argumentos adicionais do &lt;code class=&quot;language-text&quot;&gt;emit()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;eventEmitter&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;start&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;number&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;started &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;number&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

eventEmitter&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;emit&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;start&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;23&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Múltipos argumentos:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;eventEmitter&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;start&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;start&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; end&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;started from &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;start&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt; to &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;end&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

eventEmitter&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;emit&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;start&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;100&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;O objeto EventEmitter também expõe diversos outros métodos que interagem com eventos, como&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;once()&lt;/code&gt;: escuta o evento apenas uma vez&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;removeListener()&lt;/code&gt; / &lt;code class=&quot;language-text&quot;&gt;off()&lt;/code&gt;: remove um escutador (listener) de um evento&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;removeAllListeners()&lt;/code&gt;: remove todos escutadores (listeners) de um evento&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Você pode ler o detalhe de todos eles na página do módulo &lt;code class=&quot;language-text&quot;&gt;events&lt;/code&gt; em &lt;a href=&quot;https://nodejs.org/api/events.html&quot;&gt;https://nodejs.org/api/events.html&lt;/a&gt;&lt;/p&gt;
&lt;h2&gt;Construa um HTTP Server&lt;/h2&gt;
&lt;p&gt;Aqui temos um simples web server HTTP de Hello World:&lt;/p&gt;
&lt;iframe
  title=&quot;Build an HTTP Server&quot;
  src=&quot;https://glitch.com/embed/#!/embed/nodejs-dev-0037-01?path=server.js&amp;previewSize=33&amp;attributionHidden=true&amp;sidebarCollapsed=true&quot;
  alt=&quot;nodejs-dev-0037-01 on Glitch&quot;
  style=&quot;height: 400px; width: 100%; border: 0;&quot;&gt;
&lt;/iframe&gt;
&lt;!--```js
const http = require(&apos;http&apos;)

const port = 3000

const server = http.createServer((req, res) =&gt; {
  res.statusCode = 200
  res.setHeader(&apos;Content-Type&apos;, &apos;text/plain&apos;)
  res.end(&apos;Hello World\n&apos;)
})

server.listen(port, () =&gt; {
  console.log(`Server running at http://${hostname}:${port}/`)
})
```--&gt;
&lt;p&gt;Vamos analisar esse código brevemente. Nós incluimos o &lt;a href=&quot;https://nodejs.org/api/http.html&quot;&gt;módulo &lt;code class=&quot;language-text&quot;&gt;http&lt;/code&gt;&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Nós usamos o módulo para criar um servidor HTTP.&lt;/p&gt;
&lt;p&gt;É definido para o servidor escutar na porta especificada, &lt;code class=&quot;language-text&quot;&gt;3000&lt;/code&gt;. Quando o servidor está pronto, a função callback &lt;code class=&quot;language-text&quot;&gt;listen&lt;/code&gt; é chamada.&lt;/p&gt;
&lt;p&gt;A função callback que passamos é a que será executada em toda requisição. Sempre que uma nova requisição é recebida, o &lt;a href=&quot;https://nodejs.org/api/http.html#http_event_request&quot;&gt;evento &lt;code class=&quot;language-text&quot;&gt;request&lt;/code&gt;&lt;/a&gt; é chamado, fornecendo dois objetos: request (instância de &lt;a href=&quot;https://nodejs.org/api/http.html#http_class_http_incomingmessage&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;http.IncomingMessage&lt;/code&gt;&lt;/a&gt;) e response (instância de &lt;a href=&quot;https://nodejs.org/api/http.html#http_class_http_serverresponse&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;http.ServerResponse&lt;/code&gt;&lt;/a&gt;).&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;request&lt;/code&gt; contém os detalhes da requisição. Através dele, nós acessamos os cabeçalhos (headers) e os dados da requisição.&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;response&lt;/code&gt; é usado para popular os dados que vamos retornar ao cliente.&lt;/p&gt;
&lt;p&gt;No seguinte caso&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusCode &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;200&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;nós definimos a propriedade statusCode para 200, para indicar uma resposta bem sucedida.&lt;/p&gt;
&lt;p&gt;Nós também definimos a header Content-Type:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;setHeader&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Content-Type&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;text/plain&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e fechamos a resposta, adicionando o conteúdo como um argumento do &lt;code class=&quot;language-text&quot;&gt;end()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;end&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hello World\n&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Fazendo requisições HTTP com o Node.js&lt;/h2&gt;
&lt;h2&gt;Realizando uma requisição do tipo GET&lt;/h2&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; https &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;https&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; options &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  hostname&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;whatever.com&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  port&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;443&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  path&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/todos&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  method&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;GET&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; req &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; https&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;request&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;options&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;res&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;statusCode: &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusCode&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

  res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;data&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;d&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;stdout&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;write&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;d&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;error&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;error&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;end&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Realizando uma requisição do tipo POST&lt;/h2&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; https &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;https&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; data &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token constant&quot;&gt;JSON&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;stringify&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  todo&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Buy the milk&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; options &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  hostname&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;whatever.com&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  port&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;443&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  path&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/todos&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  method&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;POST&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  headers&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token string&quot;&gt;&apos;Content-Type&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;application/json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token string&quot;&gt;&apos;Content-Length&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; data&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;length
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; req &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; https&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;request&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;options&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;res&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;statusCode: &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusCode&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

  res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;data&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;d&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;stdout&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;write&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;d&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;error&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;error&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;write&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;end&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Requisições do tipos PUT e DELETE&lt;/h2&gt;
&lt;p&gt;Requisições PUT e DELETE usam o mesmo formato da requisição POST, mudando apenas o valor do &lt;code class=&quot;language-text&quot;&gt;options.method&lt;/code&gt;.&lt;/p&gt;
&lt;h2&gt;Faça um HTTP POST request com Node.js&lt;/h2&gt;
&lt;p&gt;Existem diversas maneiras de realizar uma requisição do tipo POST no Node.js, dependendo do nível de abstração que você quer utilizar.&lt;/p&gt;
&lt;p&gt;O jeito mais simples de fazer uma requisição HTTP usando Node.js é usar a &lt;a href=&quot;https://github.com/axios/axios&quot;&gt;biblioteca Axios&lt;/a&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; axios &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;axios&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

axios
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;post&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;https://whatever.com/todos&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    todo&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Buy the milk&apos;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;res&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;statusCode: &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusCode&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;res&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;error&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;error&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Utilizar o Axios requer o uso de uma biblioteca de terceiros.&lt;/p&gt;
&lt;p&gt;É possível fazer uma requisição POST usando apenas os módulos nativos do Node.js, porém é mais verboso que as duas opções anteriores:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; https &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;https&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; data &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token constant&quot;&gt;JSON&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;stringify&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  todo&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Buy the milk&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; options &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  hostname&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;whatever.com&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  port&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;443&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  path&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/todos&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  method&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;POST&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  headers&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token string&quot;&gt;&apos;Content-Type&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;application/json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    &lt;span class=&quot;token string&quot;&gt;&apos;Content-Length&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; data&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;length
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; req &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; https&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;request&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;options&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;res&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;statusCode: &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusCode&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

  res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;data&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;d&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;stdout&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;write&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;d&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;error&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;error&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;write&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;end&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Faça uma requisição GET de HTTP com body usando Node.js&lt;/h2&gt;
&lt;p&gt;Aqui temos como você pode extrair dados que foram enviados como JSON no corpo da requisição:&lt;/p&gt;
&lt;p&gt;Se você está usando Express, é bem simples: utilize o módulo &lt;code class=&quot;language-text&quot;&gt;body-parser&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Por exemplo, para obter o corpo dessa requisição:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; axios &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;axios&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

axios&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;post&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;https://whatever.com/todos&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  todo&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Buy the milk&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Esse é o código do servidor que vai receber a requisição:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; express &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;express&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; app &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;express&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

app&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;use&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;
  express&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;urlencoded&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    extended&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

app&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;use&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;express&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;json&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

app&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;post&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/todos&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;body&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;todo&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Se você não está usando Express, e você quer fazer isso em Node.js raiz, terá um pouco mais de trabalho, é claro, pois o Express abstrai muitas coisas pra você.&lt;/p&gt;
&lt;p&gt;O ponto chave pra se entender é que quando você inicializa um servidor HTTP usando &lt;code class=&quot;language-text&quot;&gt;http.createServer()&lt;/code&gt;, a callback é chamada quando o servidor obtêm todos os cabeçalhos HTTP, mas não o body (corpo da requisição).&lt;/p&gt;
&lt;p&gt;O objeto &lt;code class=&quot;language-text&quot;&gt;request&lt;/code&gt; passado na conexão de callback é uma stream.&lt;/p&gt;
&lt;p&gt;Então, nós devemos escutar pelo conteúdo do body a ser processado, e ele é processado em chunks(pedaços).&lt;/p&gt;
&lt;p&gt;Primeiro nós obtemos os dados escutando os eventos de &lt;code class=&quot;language-text&quot;&gt;data&lt;/code&gt; da stream, e quando eles finalizam, a stream emite o evento &lt;code class=&quot;language-text&quot;&gt;end&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; server &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; http&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;createServer&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// nós podemos acessar os cabeçalhos HTTP&lt;/span&gt;
  req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;data&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;chunk&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token template-string&quot;&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;Data chunk available: &lt;/span&gt;&lt;span class=&quot;token interpolation&quot;&gt;&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;${&lt;/span&gt;chunk&lt;span class=&quot;token interpolation-punctuation punctuation&quot;&gt;}&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token template-punctuation string&quot;&gt;`&lt;/span&gt;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;end&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token comment&quot;&gt;// fim dos eventos data&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Então para acessar os dados, assumindo que esperamos receber uma string, nós devemos colocá-los em um array:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; server &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; http&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;createServer&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;let&lt;/span&gt; data &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;;&lt;/span&gt;
  req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;data&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;chunk&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    data &lt;span class=&quot;token operator&quot;&gt;+=&lt;/span&gt; chunk&lt;span class=&quot;token punctuation&quot;&gt;;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  req&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;end&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token constant&quot;&gt;JSON&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;parse&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;todo &lt;span class=&quot;token comment&quot;&gt;// &apos;Buy the milk&apos;&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Trabalhando com file descriptors node Node.js&lt;/h2&gt;
&lt;p&gt;Antes que você seja capaz de interagir com um arquivo presente no seu filesystem, você deve obter um file descriptor (descritor de arquivo).&lt;/p&gt;
&lt;p&gt;Um file descriptor é o que é retornado ao abrir um arquivo utilizando o método &lt;code class=&quot;language-text&quot;&gt;open()&lt;/code&gt; do módulo &lt;code class=&quot;language-text&quot;&gt;fs&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;open&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;r&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; fd&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// fd é o nosso file descriptor&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Note o &lt;code class=&quot;language-text&quot;&gt;r&lt;/code&gt; que usamos como segundo parâmetro da chamada &lt;code class=&quot;language-text&quot;&gt;fs.open()&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Essa flag significa que nós abrimos o arquivo para leitura.&lt;/p&gt;
&lt;p&gt;Outras flags que você normalmente utilizará são:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;r+&lt;/code&gt; abre o arquivo para leitura e escrita&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;w+&lt;/code&gt; abre o arquivo para leitura e escrita, posicionando a stream no início do arquivo. O arquivo é criado se não existir.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;a&lt;/code&gt; abre o arquivo para escrita, posicionando a stream no fim do arquivo. O arquivo é criado se não existir.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;a+&lt;/code&gt; abre o arquivo para leitura e escrita, posicionando a stream no fim do arquivo. O arquivo é criado se não existir.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Você também pode abrir o arquivo utilizando o método &lt;code class=&quot;language-text&quot;&gt;fs.openSync&lt;/code&gt;, que retorna o file descriptor, em vez de fornecê-lo dentro de uma callback:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fd &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;openSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;r&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Uma vez que você obtenha o file descriptor, independentemente do método escolhido, você pode fazer todas operações que o requerem, como chamar &lt;code class=&quot;language-text&quot;&gt;fs.open()&lt;/code&gt; e muitas outras operações que interagem com o filesystem.&lt;/p&gt;
&lt;h2&gt;Node.js file stats&lt;/h2&gt;
&lt;p&gt;Todo arquivo vem com um conjunto de detalhes que nós podemos inspecionar usando Node.js.&lt;/p&gt;
&lt;p&gt;Em particular, usando o método &lt;code class=&quot;language-text&quot;&gt;stat()&lt;/code&gt; do módulo &lt;code class=&quot;language-text&quot;&gt;fs&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Você o chama passando o caminho do arquivo, e uma vez que o Node.js obtenha os detalhes do arquivo ele chamará a função callback que você passar, com 2 parâmetros: uma mensagem de erro, e os detalhes do arquivo.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;stat&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; stats&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// nós temos acesso aos detalhes do arquivo no `stats`&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;O Node.js também fornece um método síncrono, que bloqueia a thread até que os detalhes do arquivo estejam prontos:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; stats &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;statSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;As informações do arquivo estão inclusas na variável stats. Que tipos de informações nós podemos extrair usando o stats?&lt;/p&gt;
&lt;p&gt;Muitas, incluindo:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;se o arquivo é um diretório ou um arquivo, usando &lt;code class=&quot;language-text&quot;&gt;stats.isFile()&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;stats.isDirectory()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;se o arquivo é um link simbólico, usando &lt;code class=&quot;language-text&quot;&gt;stats.isSymbolicLink()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;o tamanho do arquivo, usando &lt;code class=&quot;language-text&quot;&gt;stats.size&lt;/code&gt;.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Há outros métodos avançados, mas a maior parte do que você vai usar na programação do dia a dia são esses.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;stat&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; stats&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

  stats&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;isFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// true&lt;/span&gt;
  stats&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;isDirectory&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// false&lt;/span&gt;
  stats&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;isSymbolicLink&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// false&lt;/span&gt;
  stats&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;size &lt;span class=&quot;token comment&quot;&gt;// 1024000 //= 1MB&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Node.js File Paths&lt;/h2&gt;
&lt;p&gt;Todo arquivo no sistema tem um caminho.&lt;/p&gt;
&lt;p&gt;No Linux e no macOS, um caminho tem essa cara:&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;/users/joe/file.txt&lt;/code&gt;&lt;/p&gt;
&lt;p&gt;enquanto que em computadores Windows é bem diferente, a estrutura é algo assim:&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;C:\users\joe\file.txt&lt;/code&gt;&lt;/p&gt;
&lt;p&gt;Você precisa prestar atenção quando está utilizando caminhos na sua aplicação, as diferenças devem ser levadas em consideração.&lt;/p&gt;
&lt;p&gt;Para trabalhar com caminhos, inclua esse módulo em seus arquivos:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; path &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Obtendo informações de um caminho&lt;/h2&gt;
&lt;p&gt;Dado um caminho, você pode extrair informações dele usando esses métodos:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;dirname&lt;/code&gt;: obtêm a pasta pai do arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;basename&lt;/code&gt;: obtêm a parte do nome do arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;extname&lt;/code&gt;: obtêm a parte da extensão do arquivo&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; notes &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/users/joe/notes.txt&apos;&lt;/span&gt;

path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;dirname&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;notes&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// /users/joe&lt;/span&gt;
path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;basename&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;notes&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// notes.txt&lt;/span&gt;
path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;extname&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;notes&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// .txt&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você pode obter o nome do arquivo sem a extensão ao especificar um segundo argumento no &lt;code class=&quot;language-text&quot;&gt;basename&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;basename&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;notes&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;extname&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;notes&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// notes&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Trabalhando com caminhos&lt;/h2&gt;
&lt;p&gt;Você pode unir duas ou mais partes de um caminho ao utilizar &lt;code class=&quot;language-text&quot;&gt;path.join()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; name &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;joe&apos;&lt;/span&gt;
path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;join&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;users&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; name&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;notes.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;/users/joe/notes.txt&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você pode obter o cálculo do caminho absoluto de um caminho relativo utilizando &lt;code class=&quot;language-text&quot;&gt;path.resolve()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;joe.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;/Users/joe/joe.txt&apos; se rodar a partir da minha pasta home&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Nesse caso o Nodejs vai simplesmente adicionar &lt;code class=&quot;language-text&quot;&gt;/joe.txt&lt;/code&gt; na pasta atual. Se você especificar uma pasta como segundo parâmetro, o &lt;code class=&quot;language-text&quot;&gt;resolve&lt;/code&gt; vai usar o primeiro como base pro segundo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;tmp&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;joe.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;/Users/joe/tmp/joe.txt&apos; se rodar a partir da minha pasta home&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Se o primeiro parâmetro começa com uma barra, isso implica que é um caminho absoluto:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/etc&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;joe.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;/etc/joe.txt&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;path.normalize()&lt;/code&gt; é outra função bem útil, que tentará calcular o caminho real, quando ele contêm especificadores relativos como &lt;code class=&quot;language-text&quot;&gt;.&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;..&lt;/code&gt;, ou barras duplas:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;normalize&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/users/joe/..//test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// /users/test.txt&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;&lt;strong&gt;Ambos resolve e normalize não irão validar se o caminho existe&lt;/strong&gt;. Eles só calculam um caminho baseado nas informações fornecidas.&lt;/p&gt;
&lt;h2&gt;Lendo arquivos com Node.js&lt;/h2&gt;
&lt;p&gt;O jeito mais fácil de ler um arquivo no Node.js é utilizar o método &lt;code class=&quot;language-text&quot;&gt;fs.readFile()&lt;/code&gt;, passando o caminho do arquivo, a codificação e uma função callback que será invocada com os dados do arquivo (e o erro):&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;readFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;utf8&apos;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; data&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Alternativamente, você pode usar a versão síncrona, &lt;code class=&quot;language-text&quot;&gt;fs.readFileSync()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; data &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;readFileSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;utf8&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Ambos &lt;code class=&quot;language-text&quot;&gt;fs.readFile()&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;fs.readFileSync()&lt;/code&gt; lêem todo conteúdo do arquivo em memória antes de retornar os dados.&lt;/p&gt;
&lt;p&gt;Isso significa que arquivos grandes vão causar grandes impactos no consumo de memória e na velocidade de execução do programa.&lt;/p&gt;
&lt;p&gt;Nesse caso, uma opção melhor é ler o conteúdo do arquivo usando streams.&lt;/p&gt;
&lt;h2&gt;Escrevendo arquivos com Node.js&lt;/h2&gt;
&lt;p&gt;O jeito mais fácil de escrever em arquivos com Node.js é utilizando a API &lt;code class=&quot;language-text&quot;&gt;fs.writeFile()&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; content &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Some content!&apos;&lt;/span&gt;

fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;writeFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; content&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// arquivo escrito com sucesso&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Alternativamente, você pode usar a versão síncrona, &lt;code class=&quot;language-text&quot;&gt;fs.writeFileSync()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; content &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Some content!&apos;&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; data &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;writeFileSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; content&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// arquivo escrito com sucesso&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Por padrão, essa API vai &lt;strong&gt;apagar o conteúdo do arquivo&lt;/strong&gt; se ele existir.
By default, this API will &lt;strong&gt;replace the contents of the file&lt;/strong&gt; if it does already exist.&lt;/p&gt;
&lt;p&gt;Você pode modificar o comportamento padrão especificando uma flag:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;writeFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; content&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; flag&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;a+&apos;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;As flags que você normalmente utilizará são&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;r+&lt;/code&gt; abre o arquivo para leitura e escrita&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;w+&lt;/code&gt; abre o arquivo para leitura e escrita, posicionando a stream no início do arquivo. O arquivo é criado se não existir&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;a&lt;/code&gt; abre o arquivo para escrita, posicionando a stream no fim do arquivo. O arquivo é criado se não existir&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;a+&lt;/code&gt; abre o arquivo para leitura e escrita, posicionando a stream no fim do arquivo. O arquivo é criado se não existir&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;(você pode encontrar mais flags em &lt;a href=&quot;https://nodejs.org/api/fs.html#fs_file_system_flags&quot;&gt;https://nodejs.org/api/fs.html#fs_file_system_flags&lt;/a&gt;)&lt;/p&gt;
&lt;h2&gt;Acrescentar conteúdo em um arquivo&lt;/h2&gt;
&lt;p&gt;Um método muito útil acrescentar conteúdo no fim de um arquivo é o &lt;code class=&quot;language-text&quot;&gt;fs.appendFile()&lt;/code&gt; (e sua contraparte &lt;code class=&quot;language-text&quot;&gt;fs.appendFileSync()&lt;/code&gt;):&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; content &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Some content!&apos;&lt;/span&gt;

fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;appendFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;file.log&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; content&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// feito!&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Usando streams&lt;/h2&gt;
&lt;p&gt;Todos esses métodos escrevem o conteúdo completo no arquivo antes de retornarem o controle de volta ao programa (na versão assíncrona, isso significa executar a callback)&lt;/p&gt;
&lt;p&gt;Nesse caso, uma opção melhor é escrever o conteúdo do arquivo usando streams.&lt;/p&gt;
&lt;h2&gt;Trabalhando com folders no Node.js&lt;/h2&gt;
&lt;p&gt;O módulo nativo &lt;code class=&quot;language-text&quot;&gt;fs&lt;/code&gt; do Node.js fornece diversos métodos versáteis para trabalhar com pastas.&lt;/p&gt;
&lt;h2&gt;Valide se uma pasta existe&lt;/h2&gt;
&lt;p&gt;Utilize &lt;code class=&quot;language-text&quot;&gt;fs.access()&lt;/code&gt; para validar se a pasta existe e o Node.js pode acessá-la com suas permissões.&lt;/p&gt;
&lt;h2&gt;Crie uma nova pasta&lt;/h2&gt;
&lt;p&gt;Utilize &lt;code class=&quot;language-text&quot;&gt;fs.mkdir()&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;fs.mkdirSync()&lt;/code&gt; para criar uma nova pasta.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; folderName &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test&apos;&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;!&lt;/span&gt;fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;existsSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folderName&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;mkdirSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folderName&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Leia o conteúdo de um diretório&lt;/h2&gt;
&lt;p&gt;Utilize &lt;code class=&quot;language-text&quot;&gt;fs.readdir()&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;fs.readdirSync()&lt;/code&gt; para ler os conteúdos de um diretório.&lt;/p&gt;
&lt;p&gt;Esse trecho de código lê o conteúdo de uma pasta, ambos arquivos e subpastas, e retorna o caminho relativo deles:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; path &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; folderPath &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe&apos;&lt;/span&gt;

fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;readdirSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folderPath&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você pode obter o caminho inteiro:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;readdirSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folderPath&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;map&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;fileName&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;join&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folderPath&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; fileName&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você também pode filtrar os resultados para retornar apenas os arquivos, excluindo as pastas:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;isFile&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;fileName&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;lstatSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;fileName&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;isFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;readdirSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folderPath&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;map&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;fileName&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;join&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folderPath&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; fileName&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;filter&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;isFile&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Renomeie uma pasta&lt;/h2&gt;
&lt;p&gt;Utilize &lt;code class=&quot;language-text&quot;&gt;fs.rename()&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;fs.renameSync()&lt;/code&gt; para renomear uma pasta. O primeiro parâmetro é o caminho atual, o segundo o novo caminho:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;rename&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/Users/roger&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// feito&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;fs.renameSync()&lt;/code&gt; é a versão síncrona:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;renameSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/Users/roger&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Delete uma pasta&lt;/h2&gt;
&lt;p&gt;Utilize &lt;code class=&quot;language-text&quot;&gt;fs.rmdir()&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;fs.rmdirSync()&lt;/code&gt; para deletar uma pasta.&lt;/p&gt;
&lt;p&gt;Deletar uma pasta que tem conteúdo pode ser mais complicado do que o esperado.&lt;/p&gt;
&lt;p&gt;Nesse caso é melhor instalar o módulo &lt;a href=&quot;https://www.npmjs.com/package/fs-extra&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;fs-extra&lt;/code&gt;&lt;/a&gt;, que é bem popular e atualizado. É uma substituição do módulo &lt;code class=&quot;language-text&quot;&gt;fs&lt;/code&gt;, que possui mais funcionalidades.&lt;/p&gt;
&lt;p&gt;Nesse caso o método que você quer é o &lt;code class=&quot;language-text&quot;&gt;remove()&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Instale usando&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token function&quot;&gt;npm&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;install&lt;/span&gt; fs-extra&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e use-o assim:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs-extra&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; folder &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe&apos;&lt;/span&gt;

fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;remove&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folder&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Também pode ser utilizado com promises:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;remove&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folder&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token comment&quot;&gt;//done&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;ou com async/await:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;async&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;function&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;removeFolder&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;folder&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;await&lt;/span&gt; fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;remove&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folder&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
    &lt;span class=&quot;token comment&quot;&gt;//done&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; folder &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe&apos;&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;removeFolder&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;folder&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;O módulo fs&lt;/h2&gt;
&lt;p&gt;O módulo &lt;code class=&quot;language-text&quot;&gt;fs&lt;/code&gt; disponibiliza diversas funcionalidades úteis para acessar e interagir com o file system.&lt;/p&gt;
&lt;p&gt;Não há necessidade de intalá-lo. Sendo parte do núcleo do Node.js, basta importar para poder usá-lo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Feito isso, você tem acesso a todos os métodos dele, o que inclui:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.access()&lt;/code&gt;: checa se o arquivo existe e se o Node.js pode acessá-lo com suas permissões atuais&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.appendFile()&lt;/code&gt;: acrescenta dados em um arquivo. Se o arquivo não existir, ele é criado.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.chmod()&lt;/code&gt;: muda as permissões de um arquivo especificado pelo nome que foi passado. Relacionado: &lt;code class=&quot;language-text&quot;&gt;fs.lchmod()&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;fs.fchmod()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.chown()&lt;/code&gt;: muda o proprietário e o grupo do arquivo especificado pelo nome que foi passado. Relacionado: &lt;code class=&quot;language-text&quot;&gt;fs.fchown()&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;fs.lchown()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.close()&lt;/code&gt;: fecha um descriptor de arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.copyFile()&lt;/code&gt;: copia um arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.createReadStream()&lt;/code&gt;: cria uma stream de arquivo para leitura&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.createWriteStream()&lt;/code&gt;: cria uma stream de arquivo para escrita&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.link()&lt;/code&gt;: cria um novo hard link para um arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.mkdir()&lt;/code&gt;: cria um novo diretório&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.mkdtemp()&lt;/code&gt;: cria um novo diretório temporário&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.open()&lt;/code&gt;: define o file mode&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.readdir()&lt;/code&gt;: lê os conteúdos de um diretório&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.readFile()&lt;/code&gt;: lê os conteúdos de um arquivo. Relacionado: &lt;code class=&quot;language-text&quot;&gt;fs.read()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.readlink()&lt;/code&gt;: lê o valor de um link simbólico&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.realpath()&lt;/code&gt;: resolve caminhos relativos de arquivo com ponteiros (&lt;code class=&quot;language-text&quot;&gt;.&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;..&lt;/code&gt;) para o caminho completo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.rename()&lt;/code&gt;: renomeia um arquivo ou pasta&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.rmdir()&lt;/code&gt;: deleta um diretório&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.stat()&lt;/code&gt;: retorna o status do arquivo identificado pelo nome que foi passado. Relacionado: &lt;code class=&quot;language-text&quot;&gt;fs.fstat()&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;fs.lstat()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.symlink()&lt;/code&gt;: cria um novo link simbólico para um arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.truncate()&lt;/code&gt;: trunca o arquivo identificado pelo nome que foi passado para o tamanho especificado. Relacionado: &lt;code class=&quot;language-text&quot;&gt;fs.ftruncate()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.unlink()&lt;/code&gt;: remove um arquivo ou um link simbólico&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.unwatchFile()&lt;/code&gt;: para de observar mudanças em um arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.utimes()&lt;/code&gt;: muda a timestamp do arquivo identificado pelo nome que foi passado. Relacionado: &lt;code class=&quot;language-text&quot;&gt;fs.futimes()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.watchFile()&lt;/code&gt;: começa a observar mudanças em um arquivo. Relacionado: &lt;code class=&quot;language-text&quot;&gt;fs.watch()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.writeFile()&lt;/code&gt;: escreve dados em um arquivo. Relacionado: &lt;code class=&quot;language-text&quot;&gt;fs.write()&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Uma coisa peculiar sobre o módulo &lt;code class=&quot;language-text&quot;&gt;fs&lt;/code&gt; é que todos os métodos são assíncronos por padrão, mas eles também podem rodar de forma síncrona adicionando &lt;code class=&quot;language-text&quot;&gt;Sync&lt;/code&gt; no nome.&lt;/p&gt;
&lt;p&gt;Por exemplo:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.rename()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.renameSync()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.write()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.writeSync()&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Isso faz uma enorme diferença no fluxo da sua aplicação.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;O Node.js 10 inclui &lt;a href=&quot;https://nodejs.org/api/fs.html#fs_fs_promises_api&quot;&gt;suporte experimental&lt;/a&gt; para uma API baseada em promises&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Por exemplo, vamos analisar o método &lt;code class=&quot;language-text&quot;&gt;fs.rename()&lt;/code&gt;. A API assíncrona é usada com uma callback:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;rename&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;before.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;after.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

  &lt;span class=&quot;token comment&quot;&gt;// feito&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Uma API síncrona pode ser usada com um bloco de try/catch para tratar erros:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;renameSync&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;before.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;after.json&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// feito&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;A principal diferença aqui é que a execução do seu script no segundo exemplo vai bloquear a thread, até que a operação no arquivo seja bem-sucedida.&lt;/p&gt;
&lt;h2&gt;O módulo path&lt;/h2&gt;
&lt;p&gt;O módulo &lt;code class=&quot;language-text&quot;&gt;path&lt;/code&gt; disponibiliza diversas funcionalidades úteis para acessar e interagir com o file system.&lt;/p&gt;
&lt;p&gt;Não há necessidade de intalá-lo. Sendo parte do núcleo do Node.js, basta importar para poder usá-lo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; path &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Esse módulo possui o &lt;code class=&quot;language-text&quot;&gt;path.sep&lt;/code&gt; que provê o caracter separador de segmento de caminho (&lt;code class=&quot;language-text&quot;&gt;\&lt;/code&gt; no Windows, e &lt;code class=&quot;language-text&quot;&gt;/&lt;/code&gt; no Linux / macOS), e o &lt;code class=&quot;language-text&quot;&gt;path.delimiter&lt;/code&gt; que provê o caracter delimitador de caminho (&lt;code class=&quot;language-text&quot;&gt;;&lt;/code&gt; no Windows, e &lt;code class=&quot;language-text&quot;&gt;:&lt;/code&gt; no Linux / macOS).&lt;/p&gt;
&lt;p&gt;Esses são os métodos do &lt;code class=&quot;language-text&quot;&gt;path&lt;/code&gt;:&lt;/p&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;path.basename()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Retorna a última parte de um caminho. Um segundo parâmetro pode filtrar a extensão do arquivo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;basename&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/test/something&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// something&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;basename&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/test/something.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// something.txt&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;basename&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/test/something.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// something&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;path.dirname()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Retorna a parte do diretório de um caminho:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;dirname&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/test/something&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// /test&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;dirname&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/test/something/file.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// /test/something&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;path.extname()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Retorna a parte da extensão de um caminho&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;extname&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/test/something&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;&apos;&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;extname&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/test/something/file.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;.txt&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;path.isAbsolute()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Retorna true se o caminho for absoluto&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;isAbsolute&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/test/something&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// true&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;isAbsolute&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;./test/something&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// false&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;path.join()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Junta duas ou mais partes de um caminho:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; name &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;joe&apos;&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;join&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;users&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; name&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;notes.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;/users/joe/notes.txt&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;path.normalize()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Tenta calcular o caminho correto quando ele contêm especificadores relativos como &lt;code class=&quot;language-text&quot;&gt;.&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;..&lt;/code&gt;, ou barras duplas:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;normalize&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/users/joe/..//test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;/users/test.txt&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;path.parse()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Cria um objeto contendo os segmentos que compões o caminho fornecido:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;root&lt;/code&gt;: a raiz&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;dir&lt;/code&gt;: o caminho da pasta a partir da raiz&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;base&lt;/code&gt;: o nome do arquivo + extensão&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;name&lt;/code&gt;: o nome do arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;ext&lt;/code&gt;: a extensão do arquivo&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;parse&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/users/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;resulta em&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  root&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  dir&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/users&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  base&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  ext&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  name&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;test&apos;&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;path.relative()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Aceita 2 caminhos como argumentos. Retorna o caminho relativo do primeiro para o segundo, baseando-se no diretório atual.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;relative&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;test.txt&apos;&lt;/span&gt;
&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;path&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;relative&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe/something/test.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;something/test.txt&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;path.resolve()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Você pode obter o cálculo do caminho absoluto de um caminho relativo usando &lt;code class=&quot;language-text&quot;&gt;path.resolve()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;joe.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;/Users/joe/joe.txt&apos; se rodar da minha home&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Ao especificar um segundo parâmetro, o &lt;code class=&quot;language-text&quot;&gt;resolve&lt;/code&gt; vai usar o primeiro como base para o segundo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;tmp&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;joe.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;/Users/joe/tmp/joe.txt&apos; se rodar da minha home&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Se o primeiro parâmetro começar com uma barra, isso significa que é um caminho absoluto:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;path&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;resolve&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/etc&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;joe.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;/etc/joe.txt&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;O Módulo OS&lt;/h2&gt;
&lt;p&gt;Esse módulo disponibiliza diversas funções que você pode usar para obter informações do sistema operacional e do computador em que o programa está executando, e interagir com ele.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; os &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;os&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Há algumas propriedades úteis que nos dizem algumas coisas importantes relacionadas a manipulação de arquivos:&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;os.EOL&lt;/code&gt; retorna o a sequência delimitadora de linha (caracter de pular linha). &lt;code class=&quot;language-text&quot;&gt;\n&lt;/code&gt; no Linux e macOS, e &lt;code class=&quot;language-text&quot;&gt;\r\n&lt;/code&gt; no Windows.&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;os.constants.signals&lt;/code&gt; retorna todas contantes relacionadas a sinais de processos, como SIGHUP, SIGKILL e outros.&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;os.constants.errno&lt;/code&gt; define as constantes para reportar erros, como EADDRINUSE, EOVERFLOW e mais outras.&lt;/p&gt;
&lt;p&gt;Você pode ver todas constantes em &lt;a href=&quot;https://nodejs.org/api/os.html#os_signal_constants&quot;&gt;https://nodejs.org/api/os.html#os_signal_constants&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Agora vamos ver os principais métodos do &lt;code class=&quot;language-text&quot;&gt;os&lt;/code&gt;:&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.arch()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna uma string que identifica a arquitetura, como &lt;code class=&quot;language-text&quot;&gt;arm&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;x64&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;arm64&lt;/code&gt;.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.cpus()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna informações sobre as CPUs disponívels no seu sistema.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    model&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Intel(R) Core(TM)2 Duo CPU     P8600  @ 2.40GHz&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    speed&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2400&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    times&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      user&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;281685380&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      nice&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      sys&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;187986530&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      idle&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;685833750&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      irq&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    model&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Intel(R) Core(TM)2 Duo CPU     P8600  @ 2.40GHz&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    speed&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2400&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    times&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      user&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;282348700&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      nice&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      sys&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;161800480&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      idle&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;703509470&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      irq&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.endianness()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna &lt;code class=&quot;language-text&quot;&gt;BE&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;LE&lt;/code&gt; dependendo se o Node.js foi compilado com &lt;a href=&quot;https://en.wikipedia.org/wiki/Endianness&quot;&gt;Big Endian ou Little Endian&lt;/a&gt;.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.freemem()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna o número de bytes que representam a memória livre no seu sistema.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.homedir()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna o caminho do diretório home do usuário corrente.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token string&quot;&gt;&apos;/Users/joe&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.hostname()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna o host name.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.loadavg()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna o cálculo feito pelo sistema operacional na média de carregamento.&lt;/p&gt;
&lt;p&gt;Só retorna um valor significativo no Linux e no macOS.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;3.68798828125&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;4.00244140625&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;11.1181640625&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.networkInterfaces()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna os detalhes das interfaces de rede disponíveis no seu sistema.&lt;/p&gt;
&lt;p&gt;Exemplo:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; lo0&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt;
   &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; address&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;127.0.0.1&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       netmask&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;255.0.0.0&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       family&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;IPv4&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       mac&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;fe:82:00:00:00:00&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       internal&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
     &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; address&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;::1&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       netmask&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       family&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;IPv6&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       mac&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;fe:82:00:00:00:00&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       scopeid&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       internal&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
     &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; address&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;fe80::1&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       netmask&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;ffff:ffff:ffff:ffff::&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       family&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;IPv6&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       mac&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;fe:82:00:00:00:00&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       scopeid&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       internal&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  en1&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt;
   &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; address&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;fe82::9b:8282:d7e6:496e&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       netmask&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;ffff:ffff:ffff:ffff::&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       family&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;IPv6&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       mac&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;06:00:00:02:0e:00&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       scopeid&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;5&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       internal&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;false&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
     &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; address&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;192.168.1.38&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       netmask&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;255.255.255.0&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       family&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;IPv4&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       mac&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;06:00:00:02:0e:00&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       internal&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;false&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  utun0&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt;
   &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; address&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;fe80::2513:72bc:f405:61d0&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       netmask&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;ffff:ffff:ffff:ffff::&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       family&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;IPv6&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       mac&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;fe:80:00:20:00:00&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       scopeid&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;8&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
       internal&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;false&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.platform()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna a plataforma em que o Node.js foi compilado:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;darwin&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;freebsd&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;linux&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;openbsd&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;win32&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;…outros&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.release()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna uma string que identifica o número da versão do sistema operacional&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.tmpdir()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna o caminho da pasta temp atribuida.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.totalmem()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna o número de bytes que representam o total de memória disponível no sistema.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.type()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Identifica o sistema operacional:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;Linux&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;Darwin&lt;/code&gt; no macOS&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;Windows_NT&lt;/code&gt; no Windows&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.uptime()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna o número de segundos em que o computador está rodando desde o último reinício.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;os.userInfo()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna um objeto contendo o &lt;code class=&quot;language-text&quot;&gt;username&lt;/code&gt; corrente, &lt;code class=&quot;language-text&quot;&gt;uid&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;gid&lt;/code&gt;, &lt;code class=&quot;language-text&quot;&gt;shell&lt;/code&gt;, e &lt;code class=&quot;language-text&quot;&gt;homedir&lt;/code&gt;&lt;/p&gt;
&lt;h2&gt;O módulo de eventos&lt;/h2&gt;
&lt;p&gt;O móduo &lt;code class=&quot;language-text&quot;&gt;events&lt;/code&gt; nos disponibiliza a classe EventEmitter, que é essencial para trabalhar com eventos no Node.js.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; EventEmitter &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;events&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; door &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;EventEmitter&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;O event listener usa esses eventos:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;newListener&lt;/code&gt; quando um listener é adicionado&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;removeListener&lt;/code&gt; quando um listener é removido&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Aqui detamos uma descrição detalhade dos métodos mais usados:&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.addListener()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Alias para &lt;code class=&quot;language-text&quot;&gt;emitter.on()&lt;/code&gt;.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.emit()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Emite um evento. Chama sincronamente todo event listener na ordem em que foram registrados.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;emit&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&quot;slam&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// emitindo o evento &quot;slam&quot;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.eventNames()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Retorna um array de string que representa os eventos regstrados no objeto &lt;code class=&quot;language-text&quot;&gt;EventEmitter&lt;/code&gt; atual:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;eventNames&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.getMaxListeners()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Obtêm a quantidade máxima de listeners que podem ser adicionados em um objeto &lt;code class=&quot;language-text&quot;&gt;EventEmitter&lt;/code&gt;, que por padrão é 10 mas pode ser aumentado ou diminuido utilizando &lt;code class=&quot;language-text&quot;&gt;setMaxListeners()&lt;/code&gt;&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;getMaxListeners&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.listenerCount()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Obtêm a contagem total de listeners do evento passado como parâmetro:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;listenerCount&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;open&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.listeners()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Obtêm um array de listeners do evento passado como parâmetro:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;listeners&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;open&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.off()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Alias para &lt;code class=&quot;language-text&quot;&gt;emitter.removeListener()&lt;/code&gt; adicionado no Node.js 10&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.on()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Adiciona uma função callback que é chamada quando um evento é emitido.&lt;/p&gt;
&lt;p&gt;Uso:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;open&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Door was opened&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.once()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Adiciona uma função callback que será chamada quando um evento for emitido pela primeira vez depois de registrado. Essa callback só será chamada uma vez.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; EventEmitter &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;events&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; ee &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;EventEmitter&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

ee&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;once&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;my-event&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// chama a função callback uma vez&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.prependListener()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Quando você adiciona um listener usando &lt;code class=&quot;language-text&quot;&gt;on&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;addListener&lt;/code&gt;, ele é adicionado no fim da fila de listener, e chamado por último. Usando &lt;code class=&quot;language-text&quot;&gt;preprendListener&lt;/code&gt; ele será adicionado, e chamado, antes dos outros listeners.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.prependOnceListener()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Quando você adiciona um listener usando &lt;code class=&quot;language-text&quot;&gt;once&lt;/code&gt;, ele é adicionado na fila de listeners, e chamado por último. Usando &lt;code class=&quot;language-text&quot;&gt;prependOnceListener&lt;/code&gt; ele é adicionado, e chamado, antes dos outros listeners.&lt;/p&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.removeAllListeners()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Remove todos os listeners de um objeto &lt;code class=&quot;language-text&quot;&gt;EventEmitter&lt;/code&gt; escutando um evento em específico:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;removeAllListeners&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;open&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.removeListener()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Remove um listener em específico. Você pode fazer isso salvando a função callback em uma variável, quando adicionada, ela pode ser referenciada mais tarde:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;doSomething&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;open&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; doSomething&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;removeListener&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;open&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; doSomething&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;&lt;code class=&quot;language-text&quot;&gt;emitter.setMaxListeners()&lt;/code&gt;&lt;/h2&gt;
&lt;p&gt;Define a quantidade máxima de listeners que podem ser adicionados em um objeto &lt;code class=&quot;language-text&quot;&gt;EventEmitter&lt;/code&gt;, que por padrão é 10 mas pode ser aumentado ou diminuido.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;door&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;setMaxListeners&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;50&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Módulo HTTP&lt;/h2&gt;
&lt;p&gt;O módulo HTTP é um módulo essencial para aplicações de rede em Node.js.&lt;/p&gt;
&lt;p&gt;Ele pode ser importado assim:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; http &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;http&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;O módulo disponibiliza algumas propriedades e métodos, e também algumas classes.&lt;/p&gt;
&lt;h2&gt;Properties&lt;/h2&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.METHODS&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Essa propriedade lista todos os métodos HTTP suportados:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;http&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token constant&quot;&gt;METHODS&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;ACL&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;BIND&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;CHECKOUT&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;CONNECT&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;COPY&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;DELETE&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;GET&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;HEAD&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;LINK&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;LOCK&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;M-SEARCH&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;MERGE&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;MKACTIVITY&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;MKCALENDAR&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;MKCOL&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;MOVE&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;NOTIFY&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;OPTIONS&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;PATCH&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;POST&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;PROPFIND&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;PROPPATCH&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;PURGE&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;PUT&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;REBIND&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;REPORT&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;SEARCH&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;SUBSCRIBE&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;TRACE&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;UNBIND&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;UNLINK&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;UNLOCK&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;UNSUBSCRIBE&apos;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.STATUS_CODES&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Essa propriedade lista todos os códigos de status HTTP e suas descrições:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token operator&quot;&gt;&gt;&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;http&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token constant&quot;&gt;STATUS_CODES&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;100&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Continue&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;101&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Switching Protocols&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;102&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Processing&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;200&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;OK&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;201&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Created&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;202&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Accepted&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;203&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Non-Authoritative Information&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;204&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;No Content&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;205&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Reset Content&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;206&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Partial Content&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;207&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Multi-Status&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;208&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Already Reported&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;226&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;IM Used&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;300&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Multiple Choices&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;301&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Moved Permanently&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;302&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Found&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;303&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;See Other&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;304&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Not Modified&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;305&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Use Proxy&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;307&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Temporary Redirect&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;308&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Permanent Redirect&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;400&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Bad Request&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;401&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Unauthorized&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;402&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Payment Required&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;403&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Forbidden&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;404&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Not Found&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;405&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Method Not Allowed&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;406&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Not Acceptable&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;407&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Proxy Authentication Required&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;408&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Request Timeout&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;409&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Conflict&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;410&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Gone&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;411&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Length Required&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;412&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Precondition Failed&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;413&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Payload Too Large&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;414&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;URI Too Long&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;415&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Unsupported Media Type&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;416&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Range Not Satisfiable&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;417&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Expectation Failed&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;418&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;I\&apos;m a teapot&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;421&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Misdirected Request&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;422&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Unprocessable Entity&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;423&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Locked&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;424&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Failed Dependency&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;425&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Unordered Collection&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;426&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Upgrade Required&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;428&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Precondition Required&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;429&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Too Many Requests&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;431&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Request Header Fields Too Large&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;451&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Unavailable For Legal Reasons&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;500&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Internal Server Error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;501&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Not Implemented&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;502&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Bad Gateway&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;503&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Service Unavailable&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;504&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Gateway Timeout&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;505&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;HTTP Version Not Supported&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;506&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Variant Also Negotiates&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;507&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Insufficient Storage&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;508&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Loop Detected&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;509&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Bandwidth Limit Exceeded&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;510&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Not Extended&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  &lt;span class=&quot;token string&quot;&gt;&apos;511&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Network Authentication Required&apos;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.globalAgent&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Aponta para a instância global do objeto Agente, que é uma instÂncia da classe &lt;code class=&quot;language-text&quot;&gt;http.Agent&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;É usado para gerenciar persistência de conexões e reuso para clientes HTTP.&lt;/p&gt;
&lt;p&gt;Veremos mais da descrição da classe &lt;code class=&quot;language-text&quot;&gt;http.Agent&lt;/code&gt;.&lt;/p&gt;
&lt;h2&gt;Methods&lt;/h2&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.createServer()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Retorna uma nova instância da classe &lt;code class=&quot;language-text&quot;&gt;http.Server&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Uso:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; server &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; http&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;createServer&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// gerencie cada requisição com essa callback&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.request()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Faz uma requisição HTTP para um servidor, criando uma instância da classe &lt;code class=&quot;language-text&quot;&gt;http.ClientRequest&lt;/code&gt;.&lt;/p&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.get()&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Parecido com o &lt;code class=&quot;language-text&quot;&gt;http.request()&lt;/code&gt;, mas define automaticamente o verbo HTTP para GET, e chama &lt;code class=&quot;language-text&quot;&gt;req.end()&lt;/code&gt; automaticamente.&lt;/p&gt;
&lt;h2&gt;Classes&lt;/h2&gt;
&lt;p&gt;O módulo HTTP provê 5 classes:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;http.Agent&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;http.ClientRequest&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;http.Server&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;http.ServerResponse&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;http.IncomingMessage&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.Agent&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;O Node.js cria uma instância global da classe &lt;code class=&quot;language-text&quot;&gt;http.Agent&lt;/code&gt; para gerenciar persistência de conexões e reuso para clientes HTTP.&lt;/p&gt;
&lt;p&gt;Esse objeto garante que toda requisição feita ao servidor seja enfileirada e um único socket seja reusado.&lt;/p&gt;
&lt;p&gt;Também mantém um pool de sockets. Isso é necessário por razões de performance.&lt;/p&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.ClientRequest&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Um objeto &lt;code class=&quot;language-text&quot;&gt;http.ClientRequest&lt;/code&gt; é criado quando &lt;code class=&quot;language-text&quot;&gt;http.request()&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;http.get()&lt;/code&gt; são chamados.&lt;/p&gt;
&lt;p&gt;Quando uma resposta é recebida, o evento &lt;code class=&quot;language-text&quot;&gt;response&lt;/code&gt; é chamado com a resposta, contendo uma instância de &lt;code class=&quot;language-text&quot;&gt;http.IncomingMessage&lt;/code&gt; como argumento.&lt;/p&gt;
&lt;p&gt;Os dados retornados de uma resposta podem ser lidos de 2 formas:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;você pode chamar o método &lt;code class=&quot;language-text&quot;&gt;response.read()&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;na callback do evento &lt;code class=&quot;language-text&quot;&gt;response&lt;/code&gt; você pode preparar um event listener para o evento &lt;code class=&quot;language-text&quot;&gt;data&lt;/code&gt;, assim você pode ouvir os dados transmitidos.&lt;/li&gt;
&lt;/ul&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.Server&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Essa classe é comumente instanciada e retornada quando se cria um novo servidor usando &lt;code class=&quot;language-text&quot;&gt;http.createServer()&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Uma vez que você tenha um objeto server, você pode acessar os métodos dele:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;close()&lt;/code&gt; impede o servidor de aceitar novas conexões&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;listen()&lt;/code&gt; inicia o servidor HTTP e escuta as conexões&lt;/li&gt;
&lt;/ul&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.ServerResponse&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Criado por um &lt;code class=&quot;language-text&quot;&gt;http.Server&lt;/code&gt; e passado como segundo parâmetro para o evento &lt;code class=&quot;language-text&quot;&gt;request&lt;/code&gt; acionado.&lt;/p&gt;
&lt;p&gt;Normalmente é usado com o &lt;code class=&quot;language-text&quot;&gt;res&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; server &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; http&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;createServer&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// res é um objeto http.ServerResponse&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você sempre deve chamar o método &lt;code class=&quot;language-text&quot;&gt;end()&lt;/code&gt; na callback, que fecha a response, a mensagem está completa e o servidor pode enviá-la ao client. Deve ser chamado em cada response.&lt;/p&gt;
&lt;p&gt;Esses métodos são usados para interagir com headers HTTP:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;getHeaderNames()&lt;/code&gt; obtêm a lista de nomes das headers HTTP já definidas&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;getHeaders()&lt;/code&gt; obtêm uma cópia das headers HTTP já definidas&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;setHeader(&amp;#39;headername&amp;#39;, value)&lt;/code&gt; define uma header HTTP e seu valor&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;getHeader(&amp;#39;headername&amp;#39;)&lt;/code&gt; obtêm uma header HTTP já definida&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;removeHeader(&amp;#39;headername&amp;#39;)&lt;/code&gt; remove uma header HTTP já definida&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;hasHeader(&amp;#39;headername&amp;#39;)&lt;/code&gt; retorna true se a response já contêm aquela header&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;headersSent()&lt;/code&gt; retorna true se as headers já foram enviadas ao client&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Depois de processar as headers você pode enviá-las ao client chamando &lt;code class=&quot;language-text&quot;&gt;response.writeHead()&lt;/code&gt;, que aceita o statusCode como primeiro parâmetro, e mensagem do status de forma opcional, e o objeto de headers.&lt;/p&gt;
&lt;p&gt;Para enviar os dados ao client pelo body da response, você usa &lt;code class=&quot;language-text&quot;&gt;write()&lt;/code&gt;. Ele enviará os dados armazenados em buffer para a stream de resposta HTTP.&lt;/p&gt;
&lt;p&gt;Se os headers ainda não foram enviados usando &lt;code class=&quot;language-text&quot;&gt;response.writeHead()&lt;/code&gt;, as headers serão enviadas primeiro, com o código de status e a mensagem que foram definidos na request, que você pode editar definindo os valores das propriedades &lt;code class=&quot;language-text&quot;&gt;statusCode&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;statusMessage&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;response&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusCode &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;500&lt;/span&gt;
response&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;statusMessage &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Internal Server Error&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;&lt;code class=&quot;language-text&quot;&gt;http.IncomingMessage&lt;/code&gt;&lt;/h3&gt;
&lt;p&gt;Um objeto &lt;code class=&quot;language-text&quot;&gt;http.IncomingMessage&lt;/code&gt; é criado quando:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;http.Server&lt;/code&gt; está escutando o evento &lt;code class=&quot;language-text&quot;&gt;request&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;http.ClientRequest&lt;/code&gt; está escutando o evento &lt;code class=&quot;language-text&quot;&gt;response&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Pode ser usado para acessar da response:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;status usando os métodos &lt;code class=&quot;language-text&quot;&gt;statusCode&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;statusMessage&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;headers usando o método &lt;code class=&quot;language-text&quot;&gt;headers&lt;/code&gt; ou &lt;code class=&quot;language-text&quot;&gt;rawHeaders&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;método HTTP usando o método &lt;code class=&quot;language-text&quot;&gt;method&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;versão HTTP usando o método &lt;code class=&quot;language-text&quot;&gt;httpVersion&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;URL usando o método &lt;code class=&quot;language-text&quot;&gt;url&lt;/code&gt;&lt;/li&gt;
&lt;li&gt;socket subjacente usando o método &lt;code class=&quot;language-text&quot;&gt;socket&lt;/code&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Os dados são acessados usando streams, uma vez que &lt;code class=&quot;language-text&quot;&gt;http.IncomingMessage&lt;/code&gt; implementa a interface Readable Stream.&lt;/p&gt;
&lt;h2&gt;Buffers no Node.js&lt;/h2&gt;
&lt;h2&gt;O que é um buffer?&lt;/h2&gt;
&lt;p&gt;Um buffer é uma área de memória. Desenvolvedores JavaScript não são familiarizados com esse conceito, muito menos que desenvolvedores C, C++ ou Go (ou qualquer programador que use uma linguagem de programação de sistema), que interagem com memória diariamente.&lt;/p&gt;
&lt;p&gt;Ele representa um pedaço de memória de tamanho fixo (não pode ser redimensionado) alocado fora da engine JavaScript V8.&lt;/p&gt;
&lt;p&gt;Você pode pensar em um buffer com um array de inteiros, em que cada um representa um byte de dados.&lt;/p&gt;
&lt;p&gt;Ele é implementado pela &lt;a href=&quot;https://nodejs.org/api/buffer.html&quot;&gt;classe Buffer&lt;/a&gt; no Node.js.&lt;/p&gt;
&lt;h2&gt;Por que precisamos de um buffer?&lt;/h2&gt;
&lt;p&gt;Buffers foram introduzidos para ajudar desenvolvedores a lidar com dados binários, em um ecossistema que tradicionalmente só lida com strings em vez de binários.&lt;/p&gt;
&lt;p&gt;Buffers são profundamente linkados com streams. Quando um processador de stream recebe mais rápido do que pode aguentar, ele coloca os dados em um buffer.&lt;/p&gt;
&lt;p&gt;Uma visualização simples de um buffer é quando você está assistindo um vídeo no Youtube e a linha vermelha vai além do seu ponto de visualização: você está baixando dados mais rápido do que está os vendo, e o seu browser os bufferiza.&lt;/p&gt;
&lt;h2&gt;Como criar um buffer&lt;/h2&gt;
&lt;p&gt;Um buffer é criado usando os métodos &lt;a href=&quot;https://nodejs.org/api/buffer.html#buffer_buffer_from_buffer_alloc_and_buffer_allocunsafe&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;Buffer.from()&lt;/code&gt;&lt;/a&gt;, &lt;a href=&quot;https://nodejs.org/api/buffer.html#buffer_class_method_buffer_alloc_size_fill_encoding&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;Buffer.alloc()&lt;/code&gt;&lt;/a&gt;, e &lt;a href=&quot;https://nodejs.org/api/buffer.html#buffer_class_method_buffer_allocunsafe_size&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;Buffer.allocUnsafe()&lt;/code&gt;&lt;/a&gt;.&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;from&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hey!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;ul&gt;
&lt;li&gt;&lt;a href=&quot;https://nodejs.org/api/buffer.html#buffer_class_method_buffer_from_array&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;Buffer.from(array)&lt;/code&gt;&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://nodejs.org/api/buffer.html#buffer_class_method_buffer_from_arraybuffer_byteoffset_length&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;Buffer.from(arrayBuffer[, byteOffset[, length]])&lt;/code&gt;&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://nodejs.org/api/buffer.html#buffer_class_method_buffer_from_buffer&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;Buffer.from(buffer)&lt;/code&gt;&lt;/a&gt;&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://nodejs.org/api/buffer.html#buffer_class_method_buffer_from_string_encoding&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;Buffer.from(string[, encoding])&lt;/code&gt;&lt;/a&gt;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Você também pode inicializar passando apenas o tamanho. Isso cria um buffer de 1KB:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;alloc&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;1024&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token comment&quot;&gt;//or&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;allocUnsafe&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;1024&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Enquanto ambos &lt;code class=&quot;language-text&quot;&gt;alloc&lt;/code&gt; e &lt;code class=&quot;language-text&quot;&gt;allocUnsafe&lt;/code&gt; alocam um &lt;code class=&quot;language-text&quot;&gt;Buffer&lt;/code&gt; do tamanho especificado em bytes, o &lt;code class=&quot;language-text&quot;&gt;Buffer&lt;/code&gt; criado via &lt;code class=&quot;language-text&quot;&gt;alloc&lt;/code&gt; vai ser &lt;em&gt;inicializado&lt;/em&gt; com zeros e o criado via &lt;code class=&quot;language-text&quot;&gt;allocUnsafe&lt;/code&gt; vai ser &lt;em&gt;não inicializado&lt;/em&gt;. Isso significa que enquanto &lt;code class=&quot;language-text&quot;&gt;allocUnsafe&lt;/code&gt; pode ser bem rápido em comparação ao &lt;code class=&quot;language-text&quot;&gt;alloc&lt;/code&gt;, o segmento de memória alocado pode conter dados antigos que podem ser potencialmente sensíveis.&lt;/p&gt;
&lt;p&gt;Dados antigos, se presentes em memória, podem ser acessados ou vazados quando a memória do &lt;code class=&quot;language-text&quot;&gt;Buffer&lt;/code&gt; é lida. Isso é o que realmente faz do &lt;code class=&quot;language-text&quot;&gt;allocUnsafe&lt;/code&gt; inseguro e tenha cuidado extra ao usá-lo.&lt;/p&gt;
&lt;h2&gt;Usando um buffer&lt;/h2&gt;
&lt;h3&gt;Acessando o conteúdo de um buffer&lt;/h3&gt;
&lt;p&gt;Um buffer, sendo um array de bytes, pode ser acessado como um array:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;from&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hey!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;buf&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// 72&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;buf&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// 101&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;buf&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// 121&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Esses números são o Código Unicode que identifica o caracter naquela posição do buffer (H =&gt; 72, e =&gt; 101, y =&gt; 121)&lt;/p&gt;
&lt;p&gt;Você pode imprimir o conteúdo completo de um buffer usando o método &lt;code class=&quot;language-text&quot;&gt;toString()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;buf&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;toString&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;blockquote&gt;
&lt;p&gt;Observe que se você inicializar um buffer com um número que defina o tamanho dele, você vai ter acesso à memória pre-inicializada, que vai conter dados aleatórios, não um buffer vazio!&lt;/p&gt;
&lt;/blockquote&gt;
&lt;h3&gt;Obtendo o comprimento de um buffer&lt;/h3&gt;
&lt;p&gt;Use a propriedade &lt;code class=&quot;language-text&quot;&gt;length&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;from&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hey!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;buf&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;length&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;Iterando sob o conteúdo de um buffer&lt;/h3&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;from&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hey!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;for&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; item &lt;span class=&quot;token keyword&quot;&gt;of&lt;/span&gt; buf&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;item&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// 72 101 121 33&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;Mudando o conteúdo de um buffer&lt;/h3&gt;
&lt;p&gt;Você pode gravar uma string inteira de dados em um buffer usando o método &lt;code class=&quot;language-text&quot;&gt;write()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;alloc&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;4&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
buf&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;write&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hey!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Assim como você pode acessar um buffer com uma sintaxe de array, você também pode definir os conteúdos do buffer dessa mesma forma:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;from&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hey!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
buf&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;111&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// o&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;buf&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;toString&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// Hoy!&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;Copiando um buffer&lt;/h3&gt;
&lt;p&gt;É possível copiar um buffer usando o método &lt;code class=&quot;language-text&quot;&gt;copy()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;from&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hey!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;let&lt;/span&gt; bufcopy &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;alloc&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;4&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// allocate 4 bytes&lt;/span&gt;
buf&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;copy&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;bufcopy&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Por padrão você copia o buffer inteiro. Mais 3 parâmetros deixam você definir a posição inicial, a posição final, e o comprimento do novo buffer:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;from&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hey!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;let&lt;/span&gt; bufcopy &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;alloc&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// allocate 2 bytes&lt;/span&gt;
buf&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;copy&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;bufcopy&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
bufcopy&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;toString&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// &apos;He&apos;&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h3&gt;Fatiando um buffer&lt;/h3&gt;
&lt;p&gt;Se você quer criar uma visualização parccial de um buffer, você pode criar uma fatia (slice). Uma fatia não é uma cópia: o buffer original ainda é a fonte de verdade. Se ele mudar, sua fatia também muda.&lt;/p&gt;
&lt;p&gt;Use o método &lt;code class=&quot;language-text&quot;&gt;slice()&lt;/code&gt; para criar a fatia. O primeiro parâmetro é a posição inicial, e você pode especificar um segundo parâmetro opcional com a posição final:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; buf &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; Buffer&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;from&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Hey!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
buf&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;slice&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;toString&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// Hey!&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; slice &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; buf&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;slice&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;slice&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;toString&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// He&lt;/span&gt;
buf&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;111&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// o&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;slice&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;toString&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// Ho&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Node.js Streams&lt;/h2&gt;
&lt;h2&gt;O que são streams&lt;/h2&gt;
&lt;p&gt;Streams são um dos conceitos fundamentais que empoderam aplicações Node.js.&lt;/p&gt;
&lt;p&gt;Elas são um jeito de lidar com leitura/escrita de arquivos, comunicações em rede, ou qualquer tipo de troca de informação end-to-end de uma forma eficiente.&lt;/p&gt;
&lt;p&gt;Streams não são um conceito único do Node.js. Elas foram introduzidas no sistema operacional Unix décadas atrás, permitindo que programas possam interagir uns com os outros passando streams, através do operador pipe (&lt;code class=&quot;language-text&quot;&gt;|&lt;/code&gt;).&lt;/p&gt;
&lt;p&gt;Por exemplo, em uma abordagem tradicional, quando você diz ao programa para ler um arquivo, o arquivo é lido na memória, do começo ao fim, e então é processado.&lt;/p&gt;
&lt;p&gt;Utilizando streams você lê pedaço por pedaço, processando o conteúdo sem mantê-lo completo na memória.&lt;/p&gt;
&lt;p&gt;O &lt;a href=&quot;https://nodejs.org/api/stream.html&quot;&gt;módulo &lt;code class=&quot;language-text&quot;&gt;stream&lt;/code&gt;&lt;/a&gt; provê a fundação da qual todas APIs de streaming são feitas. Todas streams são instâncias do &lt;a href=&quot;https://nodejs.org/api/events.html#events_class_eventemitter&quot;&gt;EventEmitter&lt;/a&gt;&lt;/p&gt;
&lt;h2&gt;Porquê streams&lt;/h2&gt;
&lt;p&gt;Streams basicamente nos dão duas grandes vantagens sobre outros métodos de manipulação de dados:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;strong&gt;Eficiência de memória&lt;/strong&gt;: você não precisa carregar grandes quantidades de dados em memória antes de ser capaz de processá-los&lt;/li&gt;
&lt;li&gt;&lt;strong&gt;Eficiência temporal&lt;/strong&gt;: menos tempo é requerido para começar a processar dados, uma vez que você pode começar a processar assim que os tiver, em vez de esperar até que toda carga útil de dados esteja disponível&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;Um exemplo de stream&lt;/h2&gt;
&lt;p&gt;Um exemplo típico é ler arquivos de um disco.&lt;/p&gt;
&lt;p&gt;Usando o módulo &lt;code class=&quot;language-text&quot;&gt;fs&lt;/code&gt; do Node.js, você pode ler um arquivo, e serví-lo com HTTP quando uma nova conexão é estabelecida no seu servidor HTTP:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; http &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;http&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; server &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; http&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;createServer&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token keyword&quot;&gt;function&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;readFile&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;__dirname &lt;span class=&quot;token operator&quot;&gt;+&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/data.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; data&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    res&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;end&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;data&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
server&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;listen&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;3000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;readFile()&lt;/code&gt; lê todo conteúdo do arquivo, e invoca uma função callback quando terminar.&lt;/p&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;res.end(data)&lt;/code&gt; na callbac vai retornar o conteúdo do arquivo para o client HTTP.&lt;/p&gt;
&lt;p&gt;Se o arquivo for grande, a operação vai demorar um pouco. Aqui temos a mesma funcionalidade usando streams:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; http &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;http&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; fs &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;fs&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; server &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; http&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;createServer&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;req&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; res&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; stream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; fs&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;createReadStream&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;__dirname &lt;span class=&quot;token operator&quot;&gt;+&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;/data.txt&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  stream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;pipe&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;res&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
server&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;listen&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;3000&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Em vez de esperar até que o arquivo seja completamente lido, nós começamos a “streamá-lo” para o client HTTP assim que tivermos chunks de dados prontos para serem enviados.&lt;/p&gt;
&lt;h2&gt;pipe()&lt;/h2&gt;
&lt;p&gt;O exemplo acima usa &lt;code class=&quot;language-text&quot;&gt;stream.pipe(res)&lt;/code&gt;: o método &lt;code class=&quot;language-text&quot;&gt;pipe()&lt;/code&gt; é chamado na stream de arquivo.&lt;/p&gt;
&lt;p&gt;O que esse código faz? Ele pega a origem, e canaliza para um destino.&lt;/p&gt;
&lt;p&gt;Você chama isso na stream origem, e nesse caso, a stream de arquivo é canalizada para a resposta HTTP.&lt;/p&gt;
&lt;p&gt;O valor retornado pelo método &lt;code class=&quot;language-text&quot;&gt;pipe()&lt;/code&gt; é a stream de destino, que é algo muito conveniente pois nos permite encadear múltiplas chamadas &lt;code class=&quot;language-text&quot;&gt;pipe()&lt;/code&gt;, desse jeito:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;src&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;pipe&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;dest1&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;pipe&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;dest2&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Isso faz o mesmo que&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;src&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;pipe&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;dest1&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
dest1&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;pipe&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;dest2&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;APIs Node.js baseadas em streams&lt;/h2&gt;
&lt;p&gt;Dadas as suas vantagens, muitos dos módulos principais do Node.js fornecem recursos nativos para manipulação de streams, sendo os mais notáveis:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;process.stdin&lt;/code&gt; retorna uma stream conectada ao stdin&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;process.stdout&lt;/code&gt; retorna uma stream conectada ao stdout&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;process.stderr&lt;/code&gt; retorna uma stream conectada ao stderr&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.createReadStream()&lt;/code&gt; cria uma stream de leitura para um arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;fs.createWriteStream()&lt;/code&gt; cria uma stream de escrita para um arquivo&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;net.connect()&lt;/code&gt; inicia uma stream baseada em conexão&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;http.request()&lt;/code&gt; retorna uma instância da classe http.ClientRequest, que é uma stream de escrita&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;zlib.createGzip()&lt;/code&gt; comprime dados usando gzip (um algoritmo de compressão) em uma stream&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;zlib.createGunzip()&lt;/code&gt; descomprime uma stream gzip.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;zlib.createDeflate()&lt;/code&gt; comprime dados usando deflate (um algoritmo de compressão) em uma stream&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;zlib.createInflate()&lt;/code&gt; descomprime uma stream deflate.&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;Diferentes tipos de streams&lt;/h2&gt;
&lt;p&gt;Existem quatro classes de streams:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;Readable&lt;/code&gt;: uma stream de onde você pode canalizar, mas não canalizar dados nela (você pode receber dados, mas não pode enviar dados). Quando você coloca dados em uma stream de leitura, os dados são bufferizados, até que um consumer comece a ler os dados.&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;Writable&lt;/code&gt;: uma stream em que você pode canalizar dados, mas não obter dados dela (você pode enviar dados, mas não pode receber).&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;Duplex&lt;/code&gt;: uma stream em que você pode tanto canalizar dados quando obtê-los, basicamente uma combinação de uma stream Readable e uma Writable&lt;/li&gt;
&lt;li&gt;&lt;code class=&quot;language-text&quot;&gt;Transform&lt;/code&gt;: uma stream Transform é similar a uma Duplex, mas a saída é um transform das entradas&lt;/li&gt;
&lt;/ul&gt;
&lt;h2&gt;Como criar uma stream de leitura (readable stream)&lt;/h2&gt;
&lt;p&gt;Nós obtêmos a stream de leitura pelo &lt;a href=&quot;https://nodejs.org/api/stream.html&quot;&gt;módulo &lt;code class=&quot;language-text&quot;&gt;stream&lt;/code&gt;&lt;/a&gt;, a inicializamos e implementamos o método &lt;code class=&quot;language-text&quot;&gt;readable._read()&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Primeiro crie um objeto stream:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; Stream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;stream&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; readableStream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Stream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;Readable&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;então implemente o &lt;code class=&quot;language-text&quot;&gt;_read&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function-variable function&quot;&gt;_read&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você também pode implementar o &lt;code class=&quot;language-text&quot;&gt;_read&lt;/code&gt; usando a opção &lt;code class=&quot;language-text&quot;&gt;read&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; readableStream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Stream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;Readable&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;read&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Agora que a stream está inicializada, nós podemos enviar dados a ela:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;push&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;hi!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;push&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;ho!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Como criar uma stream de escrita (writable stream)&lt;/h2&gt;
&lt;p&gt;Para criar uma stream de escrita nós extendemos o objeto base &lt;code class=&quot;language-text&quot;&gt;Writable&lt;/code&gt;, e implementamos seu método _write().&lt;/p&gt;
&lt;p&gt;Primeiro crie um objeto stream:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; Stream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;stream&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; writableStream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Stream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;Writable&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;e então implemente o &lt;code class=&quot;language-text&quot;&gt;_write&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;writableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function-variable function&quot;&gt;_write&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;chunk&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; encoding&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; next&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;chunk&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;toString&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;next&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Agora você pode canalizar uma stream de leitura nele:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;stdin&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;pipe&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;writableStream&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Como obtêr dados de uma stream de leitura&lt;/h2&gt;
&lt;p&gt;Como nós lemos dados de uma stream de leitura? Usando uma stream de escrita:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; Stream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;stream&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; readableStream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Stream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;Readable&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;read&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; writableStream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Stream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;Writable&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

writableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function-variable function&quot;&gt;_write&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;chunk&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; encoding&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; next&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;chunk&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;toString&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;next&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;pipe&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;writableStream&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;push&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;hi!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;push&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;ho!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você também pode consumir uma stream de leitura diretamente, usando o evento &lt;code class=&quot;language-text&quot;&gt;readble&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;readable&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;read&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Como enviar dados para uma stream de escrita&lt;/h2&gt;
&lt;p&gt;Usando o método &lt;code class=&quot;language-text&quot;&gt;write()&lt;/code&gt; da stream:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;writableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;write&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;hey!\n&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Sinalizando a uma stream de escrita que você terminou de escrever&lt;/h2&gt;
&lt;p&gt;Use o método &lt;code class=&quot;language-text&quot;&gt;end()&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; Stream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;stream&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; readableStream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Stream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;Readable&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;read&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; writableStream &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Stream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;Writable&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

writableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function-variable function&quot;&gt;_write&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;chunk&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; encoding&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; next&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;chunk&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;toString&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token function&quot;&gt;next&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;

readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;pipe&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;writableStream&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;push&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;hi!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
readableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;push&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;ho!&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

writableStream&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;end&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;A diferença entre development e production&lt;/h2&gt;
&lt;p&gt;Você pode ter configurações diferentes para os ambientes de produção e desenvolvimento.&lt;/p&gt;
&lt;p&gt;O Node.js assume que você está sempre rodando de um ambiente de desenvolvimento.&lt;/p&gt;
&lt;p&gt;Você pode sinalizar ao Node.js que está rodando em produção definindo a variável de ambiente &lt;code class=&quot;language-text&quot;&gt;NODE_ENV=production&lt;/code&gt;.&lt;/p&gt;
&lt;p&gt;Isso normalmente é feito executando o comando&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token builtin class-name&quot;&gt;export&lt;/span&gt; &lt;span class=&quot;token assign-left variable&quot;&gt;NODE_ENV&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt;production&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;no shell, mas é melhor colocar no seu arquivo de configuração shell (&lt;code class=&quot;language-text&quot;&gt;bash_profile&lt;/code&gt; com Bash shell), porque senão a configuração não é persistida em caso de reinício do sistema.&lt;/p&gt;
&lt;p&gt;Você também pode aplicar a variável de ambiente prefixando no comando de inicialização da sua aplicação:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;bash&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-bash line-numbers&quot;&gt;&lt;code class=&quot;language-bash&quot;&gt;&lt;span class=&quot;token assign-left variable&quot;&gt;NODE_ENV&lt;/span&gt;&lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt;production node app.js&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Essa variável de ambiente é uma convenção amplamente usada por bibliotecas também.&lt;/p&gt;
&lt;p&gt;Definir o ambiente para &lt;code class=&quot;language-text&quot;&gt;production&lt;/code&gt; geralmente garante que&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;é mantido o mínimo de logs, apenas o essencial&lt;/li&gt;
&lt;li&gt;mais níveis de cache são usados para otimizar a performance&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Tomando como exemplo o Pug, a biblioteca de templates usada pelo Express, compila em modo debug se &lt;code class=&quot;language-text&quot;&gt;NODE_ENV&lt;/code&gt; não estiver definida como &lt;code class=&quot;language-text&quot;&gt;production&lt;/code&gt;. No ambiente de desenvolvimento as views do Express são compiladas em cada requisição, enquanto que em produção elas são cacheadas. Há muitos outros exemplos além desse.&lt;/p&gt;
&lt;p&gt;Você pode usar condicionais para executar códigos em ambientes diferentes:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;env&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token constant&quot;&gt;NODE_ENV&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;===&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;development&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;//...&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;env&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token constant&quot;&gt;NODE_ENV&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;===&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;production&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;//...&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;production&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;staging&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;indexOf&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;env&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token constant&quot;&gt;NODE_ENV&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;&gt;=&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;0&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;//...&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Por exemplo, em uma aplicação Express, você pode usar isso para definir o &lt;code class=&quot;language-text&quot;&gt;errorHandler&lt;/code&gt; de acordo com o ambiente:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;env&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token constant&quot;&gt;NODE_ENV&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;===&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;development&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  app&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;use&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;express&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;errorHandler&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt; dumpExceptions&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; showStack&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token boolean&quot;&gt;true&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;

&lt;span class=&quot;token keyword&quot;&gt;if&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;env&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token constant&quot;&gt;NODE_ENV&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;===&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&quot;production&quot;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  app&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;use&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;express&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;errorHandler&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Error handling no Node.js&lt;/h2&gt;
&lt;p&gt;Erros no Node.js são tratados por meio de exceções.&lt;/p&gt;
&lt;h2&gt;Criando exceções&lt;/h2&gt;
&lt;p&gt;Uma exceção é crianda usando a palavra reservada &lt;code class=&quot;language-text&quot;&gt;throw&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;throw&lt;/span&gt; value&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Assim que o JavaScript executa essa linha, o fluxo normal do programa é parado e o controle é retomado pelo &lt;strong&gt;tratamento de exceção&lt;/strong&gt; mais próximo.&lt;/p&gt;
&lt;p&gt;Normalmente no código client-side o &lt;code class=&quot;language-text&quot;&gt;value&lt;/code&gt; pode ser qualquer valor JavaScript, incluindo uma string, um número ou um objeto.&lt;/p&gt;
&lt;p&gt;No Node.js, nós não lançamos strings, só lançamos objetos de erro.&lt;/p&gt;
&lt;h2&gt;Objetos de erro&lt;/h2&gt;
&lt;p&gt;Um objeto de erro é um objeto que é uma instância do objeto Error, ou que estenda a classe Error, fornecida pelo &lt;a href=&quot;https://nodejs.org/api/errors.html&quot;&gt;módulo nativo Error&lt;/a&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;throw&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;Ran out of coffee&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;ou&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;class&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;NotEnoughCoffeeError&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;extends&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Error&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// ...&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token keyword&quot;&gt;throw&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;NotEnoughCoffeeError&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Tratando exceções&lt;/h2&gt;
&lt;p&gt;Um bloco &lt;code class=&quot;language-text&quot;&gt;try&lt;/code&gt;/&lt;code class=&quot;language-text&quot;&gt;catch&lt;/code&gt; é um tratador de exceções.&lt;/p&gt;
&lt;p&gt;Qualquer exceção lançada nas linhas que incluem o bloco &lt;code class=&quot;language-text&quot;&gt;try&lt;/code&gt; serão tratadas no bloco &lt;code class=&quot;language-text&quot;&gt;catch&lt;/code&gt; correspondente:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;// linhas de código&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;e&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;&lt;code class=&quot;language-text&quot;&gt;e&lt;/code&gt; nesse excemplo é o valor da exceção.&lt;/p&gt;
&lt;p&gt;Você pode adicionar múltiplos blocos, que podem tratar diferentes tipos de erros.&lt;/p&gt;
&lt;h2&gt;Pegando exceções não capturadas&lt;/h2&gt;
&lt;p&gt;Se uma exceção não capturada for lançada durante a execução do seu programa, ele irá crashar.&lt;/p&gt;
&lt;p&gt;Para resolver isso, escute o evento &lt;code class=&quot;language-text&quot;&gt;uncaughtException&lt;/code&gt; no objeto &lt;code class=&quot;language-text&quot;&gt;process&lt;/code&gt;:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;on&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;uncaughtException&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;There was an uncaught error&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  process&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;exit&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token number&quot;&gt;1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token comment&quot;&gt;// obrigatório (conforme as docs do Node.js)&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Você não precisa importar o módulo nativo &lt;code class=&quot;language-text&quot;&gt;process&lt;/code&gt;, ele é automaticamente injetado.&lt;/p&gt;
&lt;h2&gt;Exceções com promises&lt;/h2&gt;
&lt;p&gt;Usando promises você pode encadear diferentes operações, e tratar erros no final:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;doSomething1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;doSomething2&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;doSomething3&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Como você sabe quando o erro ocorreu? Você na verdade não sabe, mas você pode tratar erros em cada uma das funções que chamar (&lt;code class=&quot;language-text&quot;&gt;doSomethingX&lt;/code&gt;), e dentro do catch lançar um novo erro, que chamará o &lt;code class=&quot;language-text&quot;&gt;catch&lt;/code&gt; exterior:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; &lt;span class=&quot;token function-variable function&quot;&gt;doSomething1&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;//...&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token comment&quot;&gt;//...&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token comment&quot;&gt;//... trata o erro localmente&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;throw&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;new&lt;/span&gt; &lt;span class=&quot;token class-name&quot;&gt;Error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;message&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token comment&quot;&gt;//...&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Para ser possível tratar erros localmente sem tratá-los na função que chamamos, nós podemos quebrar a corrente, você pode criar uma função em cada &lt;code class=&quot;language-text&quot;&gt;then&lt;/code&gt; e processar a exceção:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;doSomething1&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;doSomething2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token comment&quot;&gt;// trata o erro&lt;/span&gt;
      &lt;span class=&quot;token keyword&quot;&gt;throw&lt;/span&gt; err &lt;span class=&quot;token comment&quot;&gt;// quebre a corrente!&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;then&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;return&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;doSomething2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      &lt;span class=&quot;token comment&quot;&gt;// trata o erro&lt;/span&gt;
      &lt;span class=&quot;token keyword&quot;&gt;throw&lt;/span&gt; err &lt;span class=&quot;token comment&quot;&gt;// quebra a corrente!&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;catch&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;err&lt;/span&gt; &lt;span class=&quot;token operator&quot;&gt;=&gt;&lt;/span&gt; console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Tratando erros com async/await&lt;/h2&gt;
&lt;p&gt;Usando async/await, você ainda precisa tratar erros, e você pode fazer isso dessa forma:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;async&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;function&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;someFunction&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  &lt;span class=&quot;token keyword&quot;&gt;try&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    &lt;span class=&quot;token keyword&quot;&gt;await&lt;/span&gt; &lt;span class=&quot;token function&quot;&gt;someOtherFunction&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;catch&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;error&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;err&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;message&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;h2&gt;Como fazer log de um objeto no Node.js&lt;/h2&gt;
&lt;p&gt;Quando você digita &lt;code class=&quot;language-text&quot;&gt;console.log()&lt;/code&gt; em um programa JavaScript e o roda no browser, isso vai criar uma entrada bem legal no Console do Browser:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 561px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/2a5f076a9531f84a0e8e655923a55d1c/daba0/console-log-browser.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 20.32085561497326%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAECAIAAAABPYjBAAAACXBIWXMAAAsSAAALEgHS3X78AAAAqUlEQVQI11WOiQ6DIAyGff/XWzaXAR54DVAOGccU5xCTJfuSNn/SfmmzNTFrrdQspJy4sM4JEaPkXCilnLX7vm//fBKZT5Q1BqhARYXKOoo5QJc7ABWGFdbmkOPqr5/hkGMKIWitpRAjY4SQt/fbyHzbhuewDMNCaXyNUhpHxrhHbhmTp57FijPOed/3RcJau2rtum6+XR3Gjk8vYxCETYON8fBhCJnO419sSuJOsDfBRAAAAABJRU5ErkJggg==&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;log no console exibindo um objeto&quot;
        title=&quot;log no console exibindo um objeto&quot;
        src=&quot;/static/2a5f076a9531f84a0e8e655923a55d1c/daba0/console-log-browser.png&quot;
        srcset=&quot;/static/2a5f076a9531f84a0e8e655923a55d1c/00d96/console-log-browser.png 148w,
/static/2a5f076a9531f84a0e8e655923a55d1c/0b23c/console-log-browser.png 295w,
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        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Ao clicar na flecha, o log é expandido, e você pode ver claramente as propriedades do objeto:&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/176d7e6c1b9c0c0d48626733a70dace6/914f1/console-log-browser-expanded.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 38.785834738617204%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAICAIAAAB2/0i6AAAACXBIWXMAAAsSAAALEgHS3X78AAABJElEQVQY03WR2W7DIBBF8/8/1R9IqypSoliRbbwAXlhiCKuDKXFS96HteRqBDjOX2dmVummrukEYNy2kjNctTEWWXShlIYRlWcJKKmJcNnZuBXV91w+M85FQxlhRANj1eQO5kKvw4scLq5yOvHOEkKoCOci7oZ+tWarcl+UMSpNlTsrrNB0Oh2liGIbPPe64qYaQxIec5nHeMcrrYzOigVKHgAo34Sj1nM/znHJhhK01WkXOtHF37eJLjutcdx+qt5bXjBB3OYu43B836V1r4z/stir4APcY7bGYhJNEvn/o89mdTnIcn3G/c/+S058JIZIvu5siWlObek6cn45HAEBRFELIPzo/F+C9l0JqphXTVlpFlOJa3RREqChLjLExZlvYxheclckbyRFmAAAAAABJRU5ErkJggg==&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;log expandido&quot;
        title=&quot;log expandido&quot;
        src=&quot;/static/176d7e6c1b9c0c0d48626733a70dace6/799d3/console-log-browser-expanded.png&quot;
        srcset=&quot;/static/176d7e6c1b9c0c0d48626733a70dace6/00d96/console-log-browser-expanded.png 148w,
/static/176d7e6c1b9c0c0d48626733a70dace6/0b23c/console-log-browser-expanded.png 295w,
/static/176d7e6c1b9c0c0d48626733a70dace6/799d3/console-log-browser-expanded.png 590w,
/static/176d7e6c1b9c0c0d48626733a70dace6/914f1/console-log-browser-expanded.png 593w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;No Node.js, o mesmo acontece.&lt;/p&gt;
&lt;p&gt;Nós não temos tanto luxo quando logamos algo no console, porque isso vai retornar o objeto para o shell se você rodar o programa Node.js manualmente, ou para um arquivo de log. Você obtêm uma representação do objeto em formato de string.&lt;/p&gt;
&lt;p&gt;Agora, tudo fica bem até um certo nível de aninhamento. Depois de dois níveis de aninhamento, o Node.js desiste e imprime &lt;code class=&quot;language-text&quot;&gt;[Object]&lt;/code&gt; como um placeholder:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token keyword&quot;&gt;const&lt;/span&gt; obj &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  name&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;joe&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  age&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;35&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  person1&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    name&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Tony&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    age&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;50&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    person2&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      name&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Albert&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      age&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;21&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      person3&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
        name&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Peter&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
        age&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;23&lt;/span&gt;
      &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token parameter&quot;&gt;obj&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;


&lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
  name&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;joe&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  age&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;35&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
  person1&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
    name&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Tony&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    age&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;50&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
    person2&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;{&lt;/span&gt;
      name&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token string&quot;&gt;&apos;Albert&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      age&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;21&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt;
      person3&lt;span class=&quot;token punctuation&quot;&gt;:&lt;/span&gt; &lt;span class=&quot;token punctuation&quot;&gt;[&lt;/span&gt;Object&lt;span class=&quot;token punctuation&quot;&gt;]&lt;/span&gt;
    &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
  &lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;
&lt;span class=&quot;token punctuation&quot;&gt;}&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Como você pode imprimir o objeto inteiro?&lt;/p&gt;
&lt;p&gt;A melhor maneira de fazer isso, preservando a beleza da saída, é usar:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token constant&quot;&gt;JSON&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;stringify&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;obj&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;null&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;,&lt;/span&gt; &lt;span class=&quot;token number&quot;&gt;2&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;sendo &lt;code class=&quot;language-text&quot;&gt;2&lt;/code&gt; o número de espaços usados para identação.&lt;/p&gt;
&lt;p&gt;Outra opção é usar&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;js&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-js line-numbers&quot;&gt;&lt;code class=&quot;language-js&quot;&gt;&lt;span class=&quot;token function&quot;&gt;require&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;&lt;span class=&quot;token string&quot;&gt;&apos;util&apos;&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;inspect&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;defaultOptions&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;depth &lt;span class=&quot;token operator&quot;&gt;=&lt;/span&gt; &lt;span class=&quot;token keyword&quot;&gt;null&lt;/span&gt;
console&lt;span class=&quot;token punctuation&quot;&gt;.&lt;/span&gt;&lt;span class=&quot;token function&quot;&gt;log&lt;/span&gt;&lt;span class=&quot;token punctuation&quot;&gt;(&lt;/span&gt;obj&lt;span class=&quot;token punctuation&quot;&gt;)&lt;/span&gt;&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;mas o problema é que objetos aninhados com mais de 2 níveis ficam planificados, e isso pode ser um problema com objetos complexos.&lt;/p&gt;
&lt;h2&gt;Referências&lt;/h2&gt;
&lt;p&gt;Revisado, Editado e baseado na documentação oficial do NodeJS, da qual possue licença MIT, que permite a livre redistribuição.&lt;/p&gt;
&lt;p&gt;Agradecimento especial ao meu estagiário &lt;a href=&quot;http://bit.ly/teteus-rocha&quot;&gt;Matheus Rocha&lt;/a&gt; que trabalhou duro para esta apostila sair!&lt;/p&gt;
&lt;p&gt;Meu objetivo é levar conhecimento e acessibilidade a todos, muito obrigado por ter lido até aqui.&lt;/p&gt;
&lt;p&gt;Se tiver qualquer dúvida me pergunte qualquer coisa no &lt;a href=&quot;http://bit.ly/pauloluan-insta&quot;&gt;Instagram&lt;/a&gt;, faço mentoria coletiva (gratuita) para programadores iniciantes que se sentem perdidos, você será extremamente bem vindo por lá (é só clicar na imagem).&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;http://bit.ly/pauloluan-insta&quot;&gt;&lt;img src=&quot;https://media-exp1.licdn.com/dms/image/C4E12AQF9pxdMEVTSQg/article-inline_image-shrink_1500_2232/0/1614414726929?e=1619654400&amp;#x26;v=beta&amp;#x26;t=ti7w8kAyqaK7PRcB9YGnRNv8ircAgThraVR-O1D4T54&quot; alt=&quot;Mentoria Gratuita&quot;&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;Um grande abraço, Paulo Luan.&lt;/p&gt;</content:encoded></item><item><title><![CDATA[Como estudar Ciências da Computação (sem vestibular e de graça)]]></title><description><![CDATA[Lembro que quando eu fiz faculdade de computação eu tive uma grande decepção, já estava no final do segundo ano e eu ainda não estava…]]></description><link>https://blog.reativa.dev/como-estudar-ciencias-da-computacao-de-graca/</link><guid isPermaLink="false">https://blog.reativa.dev/como-estudar-ciencias-da-computacao-de-graca/</guid><pubDate>Wed, 08 Jan 2020 00:00:00 GMT</pubDate><content:encoded>&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/1351/0*yiGqqASQTW7htKxA&quot;&gt;&lt;/p&gt;
&lt;p&gt;Lembro que quando eu fiz faculdade de computação eu tive uma grande decepção, já estava no final do segundo ano e eu ainda não estava aprendendo programação. Estava vivendo um monte de rodeios, aulas aleatórias e nada de aprender ‘o que o mercado requeria’&lt;/p&gt;
&lt;h3&gt;A faculdade estava atrapalhando meus estudos…&lt;/h3&gt;
&lt;p&gt;Chegou um momento em que eu tive que fugir de algumas aulas para poder estudar.&lt;/p&gt;
&lt;p&gt;Felizmente, hoje em dia o conhecimento está acessível a todos, e eu vou te mostrar um caminho interessante para você ser o melhor programador do mercado. &lt;/p&gt;
&lt;p&gt;Não vai ser fácil, muito menos rápido… esse é um caminho de longo prazo, mas a direção eu já estou te dando, você só precisa da consistência agora :)&lt;/p&gt;
&lt;p&gt;Aliás! Existe um princípio chamado Princípio de Pareto, que diz que &lt;strong&gt;80% dos seus esforços vêm de 20% dos seus esforços&lt;/strong&gt;. Primeiro, vou te apresentar os “20%” e no final os “80%“.&lt;/p&gt;
&lt;p&gt;Sou a favor de você ter uma pegada prática primeiro (aprender como fazer aplicações de verdade, sites, aplicativos) e conseguir uma vaga de programador o mais rápido o possível.&lt;/p&gt;
&lt;p&gt;Como?? Através dos “20%” direto-ao-ponto, é só você clicar na imagem abaixo (&lt;a href=&quot;https://bit.ly/guia-dev-autodidata&quot;&gt;ou aqui&lt;/a&gt;) e me pagar uma Pizza de Mussarela 🍕 que eu te mostro.&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://bit.ly/guia-dev-autodidata&quot;&gt;&lt;img src=&quot;https://miro.medium.com/max/970/0*KUmVb8q411VJnrb-&quot; alt=&quot;Image for post&quot;&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;Ser autodidata é PRIMORDIAL na computação… se você tiver sucesso ‘se virando’ você com certeza aumentará suas chances de conseguir sucesso no mercado de trabalho.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Eu sou a favor de você adquirir &lt;a href=&quot;https://bit.ly/guia-dev-autodidata&quot;&gt;primeiro os 20% e entrar no mercado o mais rápido o possível&lt;/a&gt;, e só depois trabalhar no “longo prazo” os 80% restantes…&lt;/p&gt;
&lt;p&gt;Primeiro você tem que colocar dinheiro no seu bolso e se sustentar, isso vai abrir portas para você se educar com mais qualidade (pagar cursos mais caros, afiar o inglês e etc)&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Mas a base dos 80% é o que vai te diferenciar no longo prazo, e é extremamente importante também, então segue a grade:&lt;/p&gt;
&lt;h1&gt;Noções básicas de ciência da computação:&lt;/h1&gt;
&lt;ol&gt;
&lt;li&gt;&lt;a href=&quot;https://www.edx.org/course/cs50s-introduction-computer-science-harvardx-cs50x&quot;&gt;Introdução à ciência da computação&lt;/a&gt; Duração: 10 semanas Esforço 10—20 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/what-is-a-proof&quot;&gt;Pensamento matemático em ciência da computação&lt;/a&gt; Duração: 6 semanas Esforço 2—5 horas / semana&lt;/li&gt;
&lt;/ol&gt;
&lt;h1&gt;Programação:&lt;/h1&gt;
&lt;ol&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python&quot;&gt;Programação para todos (Introdução ao Python)&lt;/a&gt; Duração: 4 semanas Esforço 4—6 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python-data&quot;&gt;Estruturas de dados Python&lt;/a&gt; Duração: 4 semanas Esforço 4—6 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python-network-data&quot;&gt;Usando Python para acessar dados da web&lt;/a&gt; Duração: 4 semanas Esforço 4—6 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python-databases&quot;&gt;Usando bancos de dados com Python&lt;/a&gt; Duração: 3 semanas Esforço 4—8 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python-data-visualization&quot;&gt;Capstone: recuperação, processamento e visualização de dados com Python&lt;/a&gt; Duração: 2 semanas Esforço 4—6 horas / semana&lt;/li&gt;
&lt;li&gt;Alternativa: &lt;a href=&quot;https://www.coursera.org/specializations/python-3-programming&quot;&gt;Especialização em programação Python 3&lt;/a&gt; Duração: 5 meses Esforço 7 horas / semana&lt;/li&gt;
&lt;/ol&gt;
&lt;h1&gt;Matemática:&lt;/h1&gt;
&lt;ol&gt;
&lt;li&gt;&lt;a href=&quot;https://www.edx.org/course/calculus-1a-differentiation&quot;&gt;Cálculo 1A: Diferenciação&lt;/a&gt; Duração: 12 semanas Esforço 6—10 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.edx.org/course/calculus-1b-integration&quot;&gt;Cálculo 1B: Integração&lt;/a&gt; Duração: 15 semanas Esforço 6—10 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.edx.org/course/calculus-1c-coordinate-systems-infinite-mitx-18-01-3x-0&quot;&gt;Cálculo 1C: Sistemas de Coordenadas e Série Infinita&lt;/a&gt; Duração: 8 semanas Esforço 6—10 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.edx.org/course/linear-algebra-foundations-to-frontiers&quot;&gt;Álgebra Linear --- Fundamentos para Fronteiras&lt;/a&gt; Duração: 15 semanas Esforço 6—10 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/probability-intro&quot;&gt;Introdução à probabilidade e dados&lt;/a&gt; Duração: 5 semanas Esforço 5—7 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://imp.i115008.net/intro-to-statistics&quot;&gt;Introdução às estatísticas&lt;/a&gt; Duração: 8 semanas Esforço 5—7 horas / semana&lt;/li&gt;
&lt;/ol&gt;
&lt;h1&gt;Ciência de Dados:&lt;/h1&gt;
&lt;ol&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python-data-analysis&quot;&gt;Introdução à ciência de dados em Python&lt;/a&gt; Duração: 3 semanas Esforço 4—6 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python-plotting&quot;&gt;Plotagem aplicada, gráficos e representação de dados em Python&lt;/a&gt; Duração: 4 semanas Esforço 5—7 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python-machine-learning&quot;&gt;Aprendizado de máquina aplicado em Python&lt;/a&gt; Duração: 6 semanas Esforço 5—7 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python-text-mining&quot;&gt;Mineração de texto aplicada em Python&lt;/a&gt; Duração: 5 semanas Esforço 5—7 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/python-social-network-analysis&quot;&gt;Análise de rede social aplicada em Python&lt;/a&gt; Duração: 5 semanas Esforço 5—7 horas / semana&lt;/li&gt;
&lt;/ol&gt;
&lt;h1&gt;Sistemas:&lt;/h1&gt;
&lt;ol&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/build-a-computer&quot;&gt;Construa um computador moderno a partir dos primeiros princípios: de Nand a Tetris&lt;/a&gt; Duração: 6 semanas Esforço 5 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/nand2tetris2&quot;&gt;Construa um computador moderno a partir dos primeiros princípios: de Nand a Tetris II&lt;/a&gt; Duração: 6 semanas Esforço 10—15 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://imp.i115008.net/introduction-to-operating-systems&quot;&gt;Introdução aos sistemas operacionais&lt;/a&gt; Duração: 8 semanas Esforço 5—8 horas / semana&lt;/li&gt;
&lt;/ol&gt;
&lt;h1&gt;Teoria:&lt;/h1&gt;
&lt;ol&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/cs-algorithms-theory-machines&quot;&gt;Ciência da Computação: Algoritmos, Teoria e Máquinas&lt;/a&gt; Duração: 10 semanas Esforço 2—5 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/algorithms-part1&quot;&gt;Algoritmos, Parte I&lt;/a&gt; Duração: 6 semanas Esforço 6—12 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/algorithms-part2&quot;&gt;Algoritmos, Parte II&lt;/a&gt; Duração: 6 semanas Esforço 6—12 horas / semana&lt;/li&gt;
&lt;/ol&gt;
&lt;h1&gt;Bancos de dados:&lt;/h1&gt;
&lt;ol&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/database-management&quot;&gt;Fundamentos de gerenciamento de banco de dados&lt;/a&gt; Duração: 7 semanas Esforço 4—6 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/crypto&quot;&gt;Criptografia I&lt;/a&gt; Duração: 7 semanas Esforço 5 horas / semana&lt;/li&gt;
&lt;/ol&gt;
&lt;h1&gt;Unix:&lt;/h1&gt;
&lt;ol&gt;
&lt;li&gt;&lt;a href=&quot;https://imp.i115008.net/linux-command-line-basics&quot;&gt;Linux Command Line Basics&lt;/a&gt; Duração: 1 semana Esforço 5 horas / semana&lt;/li&gt;
&lt;li&gt;&lt;a href=&quot;https://www.coursera.org/learn/unix&quot;&gt;O Workbench Unix&lt;/a&gt; Duração: 4 semanas Esforço 4 horas / semana.&lt;/li&gt;
&lt;/ol&gt;
&lt;h1&gt;Princípio de Pareto&lt;/h1&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/715/0*zwnJkwUtZjUyKmNa&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;Essa base teórica que acabei de te falar vai demorar muito tempo para você terminar, e é provável que você se desmotive ao longo do tempo, e perca a constância.&lt;/p&gt;
&lt;p&gt;Ou é provável que seu inglês ainda não seja tão bom… Nesse caso a melhor solução é o &lt;a href=&quot;https://bit.ly/guia-dev-autodidata&quot;&gt;o Guia do Dev Autodidata&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Se tiver qualquer dúvida é só me perguntar &lt;a href=&quot;http://bit.ly/pauloluan-insta&quot;&gt;qualquer coisa lá no Instagram&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Um grande abraço!&lt;/p&gt;</content:encoded></item><item><title><![CDATA[Como eu consegui dois empregos de programador com este post]]></title><description><![CDATA[Este é o post original do Linkedin, olhe os comentários que o CTO da própria Buser disse a respeito do artigo: Image for post Eu não faço…]]></description><link>https://blog.reativa.dev/como-eu-consegui-dois-empregos-com-1post/</link><guid isPermaLink="false">https://blog.reativa.dev/como-eu-consegui-dois-empregos-com-1post/</guid><pubDate>Tue, 07 Jan 2020 00:00:00 GMT</pubDate><content:encoded>&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/700/0*5D1Kz5vXCE8mZacn&quot;&gt;&lt;/p&gt;
&lt;p&gt;Este é o &lt;a href=&quot;https://bit.ly/como-seduzir-startups&quot;&gt;post original do Linkedin&lt;/a&gt;, olhe os comentários que o CTO da própria Buser disse a respeito do artigo:&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/595/1*cGlO9UDpHJvfQCIhgw1frg.png&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;Eu não faço rodeios, então se eu fosse iniciante HOJE, e quisesse entrar na área o que eu faria?&lt;/p&gt;
&lt;p&gt;Passo a passo, sem enrolação e sem rodeios, primeiro a prática, depois eu explico a teoria, bora:&lt;/p&gt;
&lt;p&gt;Como funciona então um processo seletivo:&lt;/p&gt;
&lt;ol&gt;
&lt;li&gt;Você se aplica a alguma empresa (geralmente enviando CV)&lt;/li&gt;
&lt;li&gt;Alguém lê, e se a pessoa julgar que você é o candidato ideal ela te chama para uma posterior conversa.&lt;/li&gt;
&lt;li&gt;Na conversa você “vende” as suas realizações e a pessoa ficar convencida, te contrata.&lt;/li&gt;
&lt;/ol&gt;
&lt;p&gt;Baseado nisso, vamos começar.&lt;/p&gt;
&lt;p&gt;Quero te perguntar uma coisa: Você usa redes sociais? se sim, quantos segundos você dedica a olhar cada postagem rolada? 1 segundo? 4 segundos? é rápido né? você não tem paciência… Então, se nem você doa 10 segundos do seu tempo para algum post, porque é que alguém do RH perderia 5 minutos lendo um currículo chato falando prolixamente “que você se formou em sistemas de informação numa uni-esquina qualquer do período de 2009 a 2015”? 😴😴&lt;/p&gt;
&lt;p&gt;Eu focaria as minhas fichas em criar algo atraente em um primeiro contato, algo diferente de um CV convencional, mas contendo as mesmas informações.&lt;/p&gt;
&lt;p&gt;Como? um PDF, feito no Google Slides ou Canva.&lt;/p&gt;
&lt;p&gt;A primeira coisa vai ser você abrir um arquivo.txt e escrever em seu conteúdo:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Por qual motivo ela deveria me contratar?&lt;/li&gt;
&lt;li&gt;Por quais razões eu mereço mais a vaga do que os concorrentes?&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Escreva o conteúdo desse arquivo pensando: Como eu quero que a pessoa me enxergue? (ex: como autoridade em Python? JS? Como iniciante esforçado? Como Pessoa confiável? Como pessoa antifrágil? Como pessoa forte?)&lt;/p&gt;
&lt;p&gt;Ok, terminado esse arquivo, procure alguém que tenha um celular com câmera boa, vá até uma parede de cor única e tire várias fotos fazendo várias poses, apontando e etc.&lt;/p&gt;
&lt;p&gt;Agora vá no site &lt;a href=&quot;https://bit.ly/3pZC29m&quot;&gt;Remove.bg&lt;/a&gt; ou o &lt;a href=&quot;https://bit.ly/2UX0cmH&quot;&gt;Trace&lt;/a&gt; e remova o background da foto com 1 clique.&lt;/p&gt;
&lt;p&gt;Agora vá no Google Slides ou Canva e inicie um novo projeto.&lt;/p&gt;
&lt;p&gt;Agora pegue o conteúdo do txt e tente encaixar com as fotos do seu rosto.&lt;/p&gt;
&lt;p&gt;Coloque elementos da empresa também! fazendo paralelos com o que vocês estiverem em comum.&lt;/p&gt;
&lt;p&gt;Ao final exporte via PDF e você terá um resultado assim (&lt;a href=&quot;https://bit.ly/2J9NHBs&quot;&gt;CLIQUE AQUI PARA BAIXAR O PDF&lt;/a&gt;):&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;http://bit.ly/pauloluan&quot;&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*ziOHLrdohnL_iGHD&quot; alt=&quot;Image for post&quot;&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*5By3XgyfNFphD7nn&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*-vG4GuHVGkwA6qIE&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*jOq6PghLWySLhBph&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*OJf-z5zud4ysMgDZ&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://bit.ly/linkedin-longos&quot;&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*zZxD2VBs4JXhMMlI&quot; alt=&quot;Image for post&quot;&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;http://bit.ly/pauloluan-insta&quot;&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*m4tNszPEa4IOOD9i&quot; alt=&quot;Image for post&quot;&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://bit.ly/mentoria-pauloluan&quot;&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*TNXnQ8WNzu2lFnGb&quot; alt=&quot;Image for post&quot;&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*uDDOs942B6IhOszZ&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*zWvVrmKhwl5M3uXY&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*trS9Oqi1A1JT-oVz&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;&lt;img src=&quot;https://miro.medium.com/max/1500/0*Cd-YSSOXdCBPfHTr&quot; alt=&quot;Image for post&quot;&gt;&lt;/p&gt;
&lt;p&gt;Ps: Todo mundo reclama que ‘as empresas pedem experiência’ então eu montei o perfil como se eu nunca tivesse trabalhado como programador antes, e o meu objetivo seria entrar na Buser (mas vale para qualquer empresa de tech), é assim que eu me venderia, eu venderia resultados, realizações, conquistas.&lt;/p&gt;
&lt;p&gt;Foque em empresas e CEO’s low-profile, você não vai conseguir atingir a Luiza Trajano fazendo isso…&lt;/p&gt;
&lt;p&gt;Afinal, o que você quer gerar com tudo isso?&lt;/p&gt;
&lt;p&gt;Queremos gerar a sensação de que nós nos empenhamos em criar algo personalizado para a empresa, e que não somos preguiçosos e nem nos falta esforço. Que apesar da falta de experiência o fit é perfeito, e que você vai dar ‘tudo de si’ para cumprir o que prometeu.&lt;/p&gt;
&lt;p&gt;Ok, agora vem a parte técnica, empresa nenhuma quer ser sua babá, a responsabilidade da sua educação é 100% sua.&lt;/p&gt;
&lt;p&gt;Eu faria o seguinte, olharia a stack (requisitos técnicos e tecnologias que eles usam) no &lt;a href=&quot;https://jobs.buser.com.br/&quot;&gt;site de empregos&lt;/a&gt; deles:&lt;/p&gt;
&lt;p&gt;Eu faria todos os &lt;a href=&quot;https://bit.ly/3nWY5fc&quot;&gt;cursos da evolutio&lt;/a&gt; do Tony Lampada que é o CTO da empresa. Além de colocar os commits dessa jornada de cursos, eu responderia todas as dúvidas que as outras pessoas colocassem lá no fórum do curso.&lt;/p&gt;
&lt;p&gt;Eu iria mais longe ainda e juntaria todos os amigos da faculdade para fazer o curso, enviaria um e-mail para os caras da Buser e falaria:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;“Eu e mais 30 pessoas da minha faculdade estamos fazendo todos os cursos da evolutio para poder ter conhecimento da stack de vocês!&lt;/p&gt;
&lt;p&gt;Queremos muito ter contato com o mercado de trabalho de ‘verdade’, podemos agendar um dia para conhecer a operação de vocês?&lt;/p&gt;
&lt;p&gt;Força de vontade é o que mais temos, só precisamos de uma oportunidade para aprender com vocês, empresas de mercado, pois sabemos que a vida real é diferente dos hello-worlds-acadêmicos que fazemos na faculdade..”&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Outras idéias:&lt;/p&gt;
&lt;p&gt;Faria posts diários relacionados a Python e a stack deles (&lt;a href=&quot;https://bit.ly/39x6qhJ&quot;&gt;aqui eu te dou um monte de snippets ó&lt;/a&gt;), você pode usar o &lt;a href=&quot;https://bit.ly/30XrJIZ&quot;&gt;CodeCarbon&lt;/a&gt; pra gerar imagens de código e fazer pequenos posts explicativos de cada um deles.&lt;/p&gt;
&lt;p&gt;Encheria meu Github de commit de código de Python.&lt;/p&gt;
&lt;p&gt;Faria clone do CSS do site deles, simularia com Backend usando a mesma stack que eles usam nos job description e etc.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Você precisa de carteira assinada e experiência prévia para fazer isso? NÃO.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;E depois de me vender e conseguir entrar na empresa sabe o que eu faria?&lt;/p&gt;
&lt;p&gt;Under-Promise (pouca promessa) e Over-Delivery (muita entrega)&lt;/p&gt;
&lt;p&gt;Eu demonstraria dia após dia que apesar de não ter uma inteligência fora do normal e nem ser o melhor programador do mundo, eu sou o cara mais esforçado que eles já viram em toda a vida deles.&lt;/p&gt;
&lt;p&gt;Você que está lendo, só conseguirá sua oportunidade quando você souber para onde ir… Você só precisa de um objetivo certeiro, e direcionamento, e isso eu resolvo para você, &lt;a href=&quot;https://bit.ly/mentoria-pauloluan&quot;&gt;é só clicar na imagem abaixo que eu te mentoro&lt;/a&gt;, você topa?&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://bit.ly/mentoria-pauloluan&quot;&gt;&lt;img src=&quot;https://miro.medium.com/max/960/0*kWOtncUyTJPbW2it&quot; alt=&quot;Image for post&quot;&gt;&lt;/a&gt;&lt;/p&gt;</content:encoded></item><item><title><![CDATA[Como fazer as empresas saírem no tapa por você]]></title><description><![CDATA[Nós já falamos que as empresas estão desesperadas atrás de desenvolvedores, se você não leu, leia. O fato exposto no post anterior demonstra…]]></description><link>https://blog.reativa.dev/como-fazer-as-empresas-sairem-no-tapa-por-vc/</link><guid isPermaLink="false">https://blog.reativa.dev/como-fazer-as-empresas-sairem-no-tapa-por-vc/</guid><pubDate>Sun, 05 Jan 2020 00:00:00 GMT</pubDate><content:encoded>&lt;p&gt;&lt;span
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    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 100%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAUCAIAAAAC64paAAAACXBIWXMAAAsSAAALEgHS3X78AAADjUlEQVQ4y4WU3U8bRxDA/d6/oM9963MrJW+N8tCXNArCvtu9O5+PpnbStOpDm6qKVIJEWkUiShBpHCBBFgkBhUKwirGNzfnOBjvCGKjBIiQGmkaKgpIYhwC2zx+3k92jqFFUNdJoNDu7v52dnZ21wVYAXs/BqwBUPGB89Za43yNVxQZbGhSTZNdLDIUYbrNy0qz8w1sehVSYgMFk3wNVF1RPguGxkV0f2btM6t9D4zSQbwC+BvItNM6ASYdOaEhgOplBdf3AqElguCzY+ImO/1oX02kUinCTUd4f4JaX0EoOhyNobg4nUzg0iai9+VScnsEzSVx8KUJdoWnazNJpgJbZeRTTcKfX0ePj2zscURWrOu71cX23uTvD/PU+rqvH8fCR6O3jBu/y2ZxAEbPssUHd/fSJnJhGqoYHh3k9juMJPBXD+YdCJoPTaWE+g2nATEZYWBBCET4yhehiikCdwnAqFBU7vfbL17gLHfa2i/Zbg/xEGF3xOrw3OH8AbWyIw/fQz7/a6RHOnrf7BrjO6/YRPw1+ygY1z/KSpGootyz8uYhTKazpOKYhyudyQiCIVleE4CTSEzR/gWYeVVE8gXRdhKrHVn7l/q0XtXfYYzpaygo3+7lLVx2+Af5GPzc7h7u6uY6r9otXWMKBMOq/w3d1OwJBfmBIYLCx49Z08fd7/OKi8GJTojn7x9HaI5Hmtp4XaBXGxlEwjF5uSvTmtTgKhFAyiRIJkZWKvRVTAVNiZaxZxTRlIAqAq7TjMkouVlhwEeOg1A3ZNCTTsEpFYevdSFB1kqrT0jj/4HhpF6UmjyxMf26UXWurCOqyWWGzltDFykFkarEx3VgubwtjgR9H/d5o5JeV+Nlk8IzW/+nqYhMt7H6A/4atg8nbBXS+vU0N+/PZscrzaDY9onUffpz+bH0VE0P+38hVp2nIKb1Z7fk4c+3Dqb4vQr3Hnvk+SPV8lE03Q+19MDPgy/mJw7O9hx7E2x7fb79wrumE4+jQMA/wdtqud2F2ciJv5MXE3U/uq+ey6dHC2khrq8wJR2/6mv+Fa8hqye/2YdqfosVLtN0qOyINPqM2BceU+PgxdfRIsdhSfEE7yVpQFWCvlWwPkde3Kexh2zBe2RdCtak8WRP2toVyyfX3hsSuukanWthDKP/Q2IqZhRgUJmzMRfl3vpiKGxoeYngINepME+b3sBg7l0hhitDPq/DHG8hpT8857pvfAAAAAElFTkSuQmCC&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;empresas tapa&quot;
        title=&quot;empresas tapa&quot;
        src=&quot;/static/a70ec57c01e7e4412e8778a866537887/799d3/empresas_tapa.png&quot;
        srcset=&quot;/static/a70ec57c01e7e4412e8778a866537887/00d96/empresas_tapa.png 148w,
/static/a70ec57c01e7e4412e8778a866537887/0b23c/empresas_tapa.png 295w,
/static/a70ec57c01e7e4412e8778a866537887/799d3/empresas_tapa.png 590w,
/static/a70ec57c01e7e4412e8778a866537887/2a3d6/empresas_tapa.png 885w,
/static/a70ec57c01e7e4412e8778a866537887/9d22c/empresas_tapa.png 1080w&quot;
        sizes=&quot;(max-width: 590px) 100vw, 590px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Nós já falamos que &lt;a href=&quot;../empresas-desesperadas&quot;&gt;as empresas estão desesperadas atrás de desenvolvedores&lt;/a&gt;, se você não leu, leia. O fato exposto no post anterior demonstra a margem que se abriu para que possamos conseguir empregos melhores, dada a falta de programadores no mercado. Então hoje falaremos sobre dicas de como ser bem avaliado pelo RH no processo de seleção.&lt;/p&gt;
&lt;p&gt;Eu digo e repito para todos os alunos e mentorados da Reativa, de Júnior a Sênior que nos procuram: &lt;strong&gt;o RH sempre busca por provas sociais no seu perfil&lt;/strong&gt;. Se você entender as bases por trás disso você vai conseguir emprego nas melhores empresas do mundo. Esse artigo é uma pequena parte de um capítulo do &lt;a href=&quot;https://reativa.dev/&quot;&gt;nosso curso&lt;/a&gt;. Com essas dicas nossos alunos conseguiram dobrar de salário em pouquíssimo tempo.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Provas sociais são evidências que demonstram que você tem o conhecimento prático das características da vaga que a empresa tem em aberto. &lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Essas provas podem estar:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Nas empresas que você trabalhou anteriormente.&lt;/li&gt;
&lt;li&gt;Nas conexões que você possui.&lt;/li&gt;
&lt;li&gt;Nos posts técnicos que você escreveu.&lt;/li&gt;
&lt;li&gt;Na mensagem de commit que você faz.&lt;/li&gt;
&lt;li&gt;Na forma como organiza os projetos no Github.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Tudo vai ser motivo para te qualificar ou desqualificar para a vaga. Muitas vezes você é exatamente o candidato ideal, mas não se atentou a esses fatores e acabou perdendo a vaga. A análise inicial que o RH vai fazer de você é muito subjetiva, e será baseada nas informações que você coloca em seu perfil (no currículo ou Linkedin).&lt;/p&gt;
&lt;p&gt;Não tem como saber quem você é de verdade somente pelas informações do seu perfil, e é aí que você entra em posição de vantagem, porque você pode:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;&lt;strong&gt;Aprender a se vender&lt;/strong&gt;.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Pense agora, o que te leva a uma decisão de compra? Na maioria das vezes, você compra um produto pelo &lt;strong&gt;marketing&lt;/strong&gt;. A princípio você não sabe exatamente se o produto funciona bem, mas se tem imagens bonitas e um texto chamativo, esses vão ser os primeiros fatores que te levarão a comprar. No processo de contratação isso não é diferente.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;O marketing vende, mas o produto tem que ser bom. Se venda bem, mas &lt;strong&gt;NÃO MINTA JAMAIS&lt;/strong&gt;.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Já entrevistei dezenas de desenvolvedores, para vagas que variaram de estagiário a arquiteto de software sênior. Em dois minutos de conversa informal eu consigo identificar se a pessoa está mentindo. Seu &lt;strong&gt;corpo fala&lt;/strong&gt; , sua &lt;strong&gt;história fala&lt;/strong&gt; , suas &lt;strong&gt;contradições falam&lt;/strong&gt;. O contrário também acontece, mesmo quando uma pessoa está falando tudo errado pelo nervosismo, ou tem dificuldades de conversar por ter perfis introspectivos, a gente consegue identificar se ela é potencial, se ela se esforça e se realmente quer melhorar. Foque em &lt;strong&gt;ser&lt;/strong&gt; , e não em &lt;strong&gt;parecer&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;É a tecla que nós da &lt;a href=&quot;http://reativa.dev/&quot;&gt;Reativa&lt;/a&gt; sempre batemos: Procure ser o desenvolvedor que &lt;strong&gt;estuda muito&lt;/strong&gt;, que trabalha &lt;strong&gt;duro e sem preguiça&lt;/strong&gt;, que programa muito, que verdadeiramente entrega valor para a comunidade, &lt;strong&gt;independente do seu nível&lt;/strong&gt;. Não vai ser fácil, mas se você se tornar essa pessoa, até em uma conversa de bar qualquer um vai identificar que você é diferenciado.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Sorte é a &lt;strong&gt;oportunidade&lt;/strong&gt; aliada com a &lt;strong&gt;preparação&lt;/strong&gt;. &lt;strong&gt;Esteja sempre preparado&lt;/strong&gt;.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;A dica desse contexto é: vá a eventos, observe, converse com as pessoas, procure gerar valor para elas e &lt;strong&gt;uma hora vai dar bom&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Tendo isso em mente, vamos começar a trabalhar no seu perfil com as dicas práticas. Eu recomendaria você começar a trabalhar todos os dias para criar provas sociais que demonstrem que você é muito melhor do que os outros candidatos. Mas como?&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Posts técnicos de snippets de código e dicas úteis no Linkedin.&lt;/li&gt;
&lt;li&gt;Posts em blog pessoal, Medium ou Linkedin sobre como você resolveu algum problema técnico imenso e detalhes com exemplos de código. (Escrever duas versões do post, uma em inglês e outra em português).&lt;/li&gt;
&lt;li&gt;Um Github com códigos que funcionem e que tenham integração contínua, testes unitários e readmes extremamente bem escritos.&lt;/li&gt;
&lt;li&gt;Programar em inglês e usar boas práticas no código do Github.&lt;/li&gt;
&lt;li&gt;Apagar os repositórios feios que você tem no seu Github (é melhor ter 3 bons do que 50 ruins).&lt;/li&gt;
&lt;li&gt;Interagir e contribuir com projetos existentes no Github.&lt;/li&gt;
&lt;li&gt;Mensagens de commit com o código bem separado e com mensagens muito descritivas e EM INGLÊS.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Faça cadência de posts no Linkedin, comece a escrever como se você fosse um grande arquiteto de software, mas sempre com humildade, sempre respondendo as pessoas que comentarem e tentando ajudar verdadeiramente.&lt;/p&gt;
&lt;p&gt;Exemplo de post bom para o Linkedin:&lt;/p&gt;
&lt;p&gt; &lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 545px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/038c83bde47a194b37e3e0f9769a7046/3af27/exemplo1.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 67.1559633027523%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;exemplo1&quot;
        title=&quot;exemplo1&quot;
        src=&quot;/static/038c83bde47a194b37e3e0f9769a7046/3af27/exemplo1.png&quot;
        srcset=&quot;/static/038c83bde47a194b37e3e0f9769a7046/00d96/exemplo1.png 148w,
/static/038c83bde47a194b37e3e0f9769a7046/0b23c/exemplo1.png 295w,
/static/038c83bde47a194b37e3e0f9769a7046/3af27/exemplo1.png 545w&quot;
        sizes=&quot;(max-width: 545px) 100vw, 545px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Isso gera prova social, mostra que você se esforçou, mostra que você entende de Github, que você contribui com conhecimento para os outros DEVS. Na hora da avaliação, isso faz com que o seu salário suba, pois você será avaliado como um DEV mais avançado, por mais que você seja Júnior.&lt;/p&gt;
&lt;p&gt;Provas sociais do post:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Usa Github (tem experiência).&lt;/li&gt;
&lt;li&gt;Já passou por muitas etapas para conseguir chegar até o resultado que ele postou (experiência).&lt;/li&gt;
&lt;li&gt;Fez o curso online e terminou os exercício (provou ter prestado atenção no curso e que é autodidata).&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Outro exemplo:&lt;/p&gt;
&lt;p&gt; &lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 533px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/c816d5d6408cdddd5db334af51ae8a2f/51e5c/exemplo2.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 68.85553470919325%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;exemplo2&quot;
        title=&quot;exemplo2&quot;
        src=&quot;/static/c816d5d6408cdddd5db334af51ae8a2f/51e5c/exemplo2.png&quot;
        srcset=&quot;/static/c816d5d6408cdddd5db334af51ae8a2f/00d96/exemplo2.png 148w,
/static/c816d5d6408cdddd5db334af51ae8a2f/0b23c/exemplo2.png 295w,
/static/c816d5d6408cdddd5db334af51ae8a2f/51e5c/exemplo2.png 533w&quot;
        sizes=&quot;(max-width: 533px) 100vw, 533px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Demonstra que ele gosta de lógica de programação e dá a entender que programação é uma diversão na vida dele. Eu particularmente quando contrato desenvolvedores gosto de perceber que ele gosta MUITO do que faz, isso vai fazer com que ele não surte quando tiver problemas complexos do trabalho para resolver.&lt;/p&gt;
&lt;p&gt;Outro exemplo:&lt;/p&gt;
&lt;p&gt; &lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 558px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/1fe995c3d5edf498b2c20928ee397d39/f4410/exemplo3.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 80.64516129032259%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;exemplo3&quot;
        title=&quot;exemplo3&quot;
        src=&quot;/static/1fe995c3d5edf498b2c20928ee397d39/f4410/exemplo3.png&quot;
        srcset=&quot;/static/1fe995c3d5edf498b2c20928ee397d39/00d96/exemplo3.png 148w,
/static/1fe995c3d5edf498b2c20928ee397d39/0b23c/exemplo3.png 295w,
/static/1fe995c3d5edf498b2c20928ee397d39/f4410/exemplo3.png 558w&quot;
        sizes=&quot;(max-width: 558px) 100vw, 558px&quot;
        loading=&quot;lazy&quot;
      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Nós podemos ver que o perfil dela é de auxiliar de escritório e que ela está aprendendo programação, demonstrando que é esforçada e muitas vezes só isso já é suficiente para o RH te querer. Às vezes eles vão aceitar te contratar pelo seu potencial e não pela sua capacidade técnica atual.&lt;/p&gt;
&lt;p&gt;Só nessa imagem vimos que ela usou a Udemy, ou seja, ela &lt;strong&gt;investiu dinheiro do próprio bolso&lt;/strong&gt; para pagar um curso, demonstrando que é &lt;strong&gt;EXTREMAMENTE INTERESSADA&lt;/strong&gt;. Outro ponto é que ela usa Visual Code, então ela &lt;strong&gt;já passou por diversas etapas&lt;/strong&gt; até chegar naquele resultado.&lt;/p&gt;
&lt;p&gt;Provas Sociais:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Usou dinheiro do bolso para investir num curso (interessada).&lt;/li&gt;
&lt;li&gt;Apesar de outra profissão, está aprendendo programação (interessada).&lt;/li&gt;
&lt;li&gt;Usou VS Code (tem experiência).&lt;/li&gt;
&lt;li&gt;Postou no Linkedin (é aberta a crítica, tem coragem de demonstrar publicamente e ser criticada).&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Próximo Exemplo:&lt;/p&gt;
&lt;p&gt; &lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 542px;&quot;
    &gt;
      &lt;a
    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/233dff801e1cb1ca8166f1f74b31c14c/b4155/exemplo4.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
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  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;exemplo4&quot;
        title=&quot;exemplo4&quot;
        src=&quot;/static/233dff801e1cb1ca8166f1f74b31c14c/b4155/exemplo4.png&quot;
        srcset=&quot;/static/233dff801e1cb1ca8166f1f74b31c14c/00d96/exemplo4.png 148w,
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  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Começou o post fazendo uma crítica, que dá a entender que ele já passou por diversas situações e está alertando outras pessoas a não fazerem o mesmo.&lt;/p&gt;
&lt;p&gt;O ponto positivo é que ele está &lt;strong&gt;preocupado&lt;/strong&gt; com a forma como as pessoas se comportam e que você melhore com o erro dos outros. O lado negativo é que você pode ser &lt;strong&gt;interpretado como reclamão&lt;/strong&gt; e que só está criticando os outros para mostrar que você é melhor que eles.&lt;/p&gt;
&lt;p&gt;A diferença do veneno e do remédio é a quantidade, então o segredo é saber &lt;strong&gt;dosar&lt;/strong&gt; e abusar do &lt;strong&gt;bom senso&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Nesse caso o rapaz tinha autoridade para falar, porque já tinha um cargo alto em uma empresa, o que faz com que as pessoas acabem respeitando a primeira vista. No caso de um junior tomar a mesma posição, ele teria que utilizar outra forma de comunicação, como por exemplo:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;“Eu sou muito observador, e o fato de eu ainda ocupar uma posição de júnior me faz querer aprender com o comportamento dos devs mais experientes.&lt;/p&gt;
&lt;p&gt;Reparei que existem muitos bons exemplos de inspiração, mas também vejo muita gente que estagnou na carreira, o que eu não busco jamais para a minha forma de trabalhar.&lt;/p&gt;
&lt;p&gt;Criei uma lista do que eu aprendi e do que eu busco evitar, de forma com que eu cresça mais rápido na minha carreira. Meu objetivo é o de deixar claro o que eu não devo fazer, não sendo um ataque pessoal a ninguém. Então vamos a lista dos erros a evitar:&lt;/p&gt;
&lt;p&gt;1- Vaidade, por achar que o código dele é sempre o melhor, e não aceitar críticas ou code reviews.
[…]”&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Dessa forma eu deixaria muito bem exemplificado e muito explícito de que eu sou muito humilde e que busco melhorar sempre.&lt;/p&gt;
&lt;p&gt;Lembre-se: &lt;strong&gt;tudo é prova social&lt;/strong&gt;. Fazer isso gera engajamento, e engajamento gera visualização tanto de outros devs quanto de RH, o que pode gerar contatos para você.&lt;/p&gt;
&lt;p&gt;Uma dica adicional seria de no fim do post você colocar:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;“O que você acha que faltou nessa lista?
Ps: Se alguém quiser tomar um café para falarmos sobre possíveis oportunidades para programador Júnior, me chame no privado, estou em busca de recolocação para posições em React e NodeJS. Tenho disponibilidade para mudança de cidade.”&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Repare:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Primeiro você gerou valor gratuitamente.&lt;/li&gt;
&lt;li&gt;Provou ter passado por muitas situações.&lt;/li&gt;
&lt;li&gt;É decidido sobre onde quer chegar na carreira.&lt;/li&gt;
&lt;li&gt;Sabe escrever e não tem vergonha de se expôr.&lt;/li&gt;
&lt;li&gt;É organizado e focado em melhorar&lt;/li&gt;
&lt;li&gt;Tem experiência de vida e ainda está disponível?
QUERO ESSE DEV AGORA NA MINHA EQUIPE!&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Mesmo em caso de você não ter experiência, as pessoas vão te dar uma chance, pois você prova que o que está dizendo é verdade através da geração de valor, das dicas para os outros devs, e que você não só está preocupado com a sua mudança, mas a de possíveis outras pessoas.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;DICA PARA QUEM ESTÁ COMEÇANDO&lt;/strong&gt;: Empresas contratam potenciais, porque eles &lt;strong&gt;são baratos&lt;/strong&gt; e é muito difícil encontrar &lt;strong&gt;gente esperta&lt;/strong&gt;. Criando esse tipo de post do exemplo, você demonstra &lt;strong&gt;criatividade&lt;/strong&gt; e não se coloca em posição de vítima só esperando pela “recolocação cair no seu colo”.&lt;/p&gt;
&lt;p&gt;Pra quem não sabe o que quer, qualquer lugar serve. Mas os devs que querem estar em primeiro lugar, estão com a mentoria da Reativa.&lt;/p&gt;
&lt;p&gt;Nossos conteúdos são focados em conhecimentos práticos da vida real de um programador, através deles, ajudamos você a impulsionar a sua carreira e te levar de Dev Junior a Sênior no menor tempo o possível. Esse post foi só uma pequena pílula do que a Reativa oferece. Depoimentos dos nossos mentorados:&lt;/p&gt;
&lt;p&gt; &lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 405px;&quot;
    &gt;
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    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/4bdd06474a0b17ad3d5e0728c717cd6e/2a118/depoimento1.png&quot;
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    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 143.20987654320987%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
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  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;O &lt;a href=&quot;https://www.linkedin.com/in/mateus-passos-amaral/&quot;&gt;Mateus&lt;/a&gt;, é desenvolvedor júnior que busca recolocação e está no processo de mentoria.&lt;/p&gt;
&lt;p&gt; &lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 412px;&quot;
    &gt;
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    href=&quot;/static/d1b637092d3b7abe5738498769842117/f5bbb/depoimento2.png&quot;
    style=&quot;display: block&quot;
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    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 33.00970873786408%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAHCAIAAACHqfpvAAAACXBIWXMAAAsSAAALEgHS3X78AAAA30lEQVQY03WQ3UrEMBCF8/Je+QKC4LV3XvgAPoC7vbHbhYrFdiXkv3ZtE2syzU6sBZXtBxkGkpw5c4j3Xgm+3zzaoZdSMC6sdTFGAJgWfvcI3rZt23Udcc6V+/z68oIzWhRFvtspZebPMb2bvut/mqahlJK4zjwFD6xAHu7vJKXWfTLGtNaoxzkXQnAh+3fxoV6Psg5+PCtNbm+u6pfnACClxE2w6oRS2gxHPZi33hwgfJ21RtYMQwjeBw+Y1jSOo8UY/5Jsz0n+bLiEmVIsyzzxlGXbqqowW/RjFrBHuRMUqpCJm7pjQQAAAABJRU5ErkJggg==&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;depoimento2&quot;
        title=&quot;depoimento2&quot;
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  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;O &lt;a href=&quot;https://www.linkedin.com/in/alexandrefeio/&quot;&gt;Alexandre&lt;/a&gt; é desenvolvedor pleno em transição para sênior, e também está no processo de mentoria.&lt;/p&gt;
&lt;p&gt;Desejamos todo o sucesso do mundo para todos vocês.&lt;/p&gt;
&lt;p&gt;Qual conteúdo vocês gostariam de ver aqui na Reativa? Gostou? Não gostou? Sua opinião importa muito, comente! Não se esqueça de marcar os amigos que precisam de ajuda na recolocação, e somente marcando eles nesse post e compartilhando você poderá ajudar outras pessoas.&lt;/p&gt;
&lt;p&gt;Acompanhe a Reativa nas redes sociais:&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://www.instagram.com/reativatecnologia&quot;&gt;Instagram&lt;/a&gt; - &lt;a href=&quot;https://www.facebook.com/reativaschool&quot;&gt;Facebook&lt;/a&gt; - &lt;a href=&quot;http://reativa.dev/&quot;&gt;Site&lt;/a&gt; - &lt;a href=&quot;http://blog.reativa.dev/&quot;&gt;Blog&lt;/a&gt;.&lt;/p&gt;</content:encoded></item><item><title><![CDATA[Como ganhar R$ 10 mil por mês]]></title><description><![CDATA[O sonho da maioria das pessoas é o de ganhar um salário de 5 digitos por mês. Para alguns é um sonho bastante difícil de atingir, mas vou te…]]></description><link>https://blog.reativa.dev/como-ganhar-10mil-por-mes/</link><guid isPermaLink="false">https://blog.reativa.dev/como-ganhar-10mil-por-mes/</guid><pubDate>Sat, 04 Jan 2020 00:00:00 GMT</pubDate><content:encoded>&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
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    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/2bcc3ff66c76d80800a1f3e6b608424d/9d22c/10mil.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 100%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
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        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;10mil&quot;
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    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;O sonho da maioria das pessoas é o de ganhar um salário de 5 digitos por mês. Para alguns é um sonho bastante difícil de atingir, mas vou te mostrar como qualquer um, com qualquer profissão, pode conseguir isso.&lt;/p&gt;
&lt;p&gt;Uma das profissões que mais crescem no mundo e que vai te proporcionar o caminho mais rápido para ganhar 10 mil por mês é  &lt;a href=&quot;https://reativa.dev/&quot;&gt;se tornando programador&lt;/a&gt;. Muito dinheiro está entrando nesse mercado &lt;strong&gt;e agora é o melhor momento para começar&lt;/strong&gt;, e se você deixar essa oportunidade passar, poderá se arrepender. Enquanto isso, outras pessoas estão aproveitando a oportunidade e ganhando muito dinheiro… (&lt;a href=&quot;http://bit.ly/form-reativa&quot;&gt;clique aqui e deixe seu email&lt;/a&gt; que te diremos como você pode acelerar sua carreira como desenvolvedor e ganhar dinheiro mais rapidamente).&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Esse texto é longo, mas é honesto em sua proposta. Leia e releia com paciência até o fim, pois poderá  mudar sua visão de vida e seus planos para o futuro.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Hoje a história vai ser de um menina chamada Paula, uma garota que nasceu na periferia de São José dos Campos, mas foi sempre muito ambiciosa. Seu sonho sempre foi ganhar muito dinheiro. Exímia autodidata, foi atrás de respostas e em busca da fórmula do dinheiro mágico. Foi enganada e entrou em pirâmides, quebrou com criptomoedas, perdeu dinheiro em investimentos arriscados da bolsa, mas nunca desistiu do sonho de ser rica e de entender as lógicas por trás da riqueza.&lt;/p&gt;
&lt;p&gt;O que ela ainda não tinha percebido, é que o que faltava para ela &lt;strong&gt;NÃO era&lt;/strong&gt; a coragem e trabalho duro, mas &lt;strong&gt;visão&lt;/strong&gt; (em ambos os sentidos, por ser míope no olho e também na forma de pensar). Ela percebeu que não conseguia enxergar &lt;strong&gt;o motivo pelo qual ela não ganhava muito dinheiro&lt;/strong&gt;. &lt;/p&gt;
&lt;p&gt;Um vídeo que a fez perceber sua falta de visão sobre os motivos dos fracassos na vida dela foi esse aqui (&lt;strong&gt;é MUITO importante que você veja o vídeo&lt;/strong&gt;).&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;EU DÚVIDO QUE VOCÊ ACERTE QUANTOS PASSES DE BOLA O TIME DE BRANCO FEZ. 99% DAS PESSOAS ERRAM POR FALTA DE ATENÇÃO.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;&lt;iframe width=&quot;100%&quot; height=&quot;315&quot; src=&quot;https://www.youtube-nocookie.com/embed/FzeXeXR9cCs?rel=0&quot; frameBorder=&quot;0&quot; allow=&quot;accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture&quot; allowFullScreen&gt;&lt;/iframe&gt;&lt;/p&gt;
&lt;p&gt;Vou comentar sobre o vídeo um pouco mais abaixo.&lt;/p&gt;
&lt;p&gt;Continuando… Certa vez, Paula também assistium um discurso do Steve Jobs:&lt;/p&gt;
&lt;p&gt;&lt;div class=&quot;gatsby-resp-iframe-wrapper&quot; style=&quot;padding-bottom: 75%; position: relative; height: 0; overflow: hidden; margin-bottom: 1.0725rem&quot; &gt; &lt;iframe src=&quot;https://www.youtube.com/embed/ugcVdpGQGwI?feature=oembed&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen style=&quot; position: absolute; top: 0; left: 0; width: 100%; height: 100%; &quot;&gt;&lt;/iframe&gt; &lt;/div&gt;&lt;/p&gt;
&lt;p&gt;Que em resumo dizia:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Você não consegue ligar os pontos olhando pra frente; Você só consegue ligá-los olhando pra trás. Então você tem que confiar que os pontos se ligarão algum dia no futuro. Você tem que confiar em algo – seu instinto, destino, vida, carma, o que for. Esta abordagem nunca me desapontou, e fez toda diferença na minha vida.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Ela então percebeu que tinha que &lt;strong&gt;aumentar a sua visão&lt;/strong&gt; sobre o dinheiro para conseguir enxergar onde ela estava errando, pois percebeu que existiam determinados padrões na riqueza, mas ainda não sabia como conectar os pontos.&lt;/p&gt;
&lt;p&gt;Partiu então para a leitura do principal livro de riqueza do mundo, que era uma leitura obrigatória para quem quer enriquecer, “Pense e Enriqueça” do Napoleon Hill, um homem que &lt;a href=&quot;https://idiomus.com/blog/napoleon-hill/&quot;&gt;tinha dedicado a sua vida em prol do estudo da riqueza&lt;/a&gt;, e sobre qual eram os motivos que levaram as pessoas mais ricas do mundo a serem ricas.&lt;/p&gt;
&lt;p&gt;Ela sempre ouvia resumos dos livros quando queria economizar tempo, usando o &lt;a href=&quot;https://www.resumocast.com.br/003-pense-e-enriqueca/&quot;&gt;Resumo Cast&lt;/a&gt; e o &lt;a href=&quot;https://anchor.fm/idiomus&quot;&gt;Idiomus&lt;/a&gt;, mas também &lt;a href=&quot;https://www.youtube.com/watch?v=ophyriC5Y7w&quot;&gt;ouviu o audiobook completo&lt;/a&gt; e leu o &lt;a href=&quot;https://www.amazon.com/Quem-Pensa-Enriquece-Portugues-Brasil/dp/8576766302&quot;&gt;livro físico&lt;/a&gt;. Fica a dica.&lt;/p&gt;
&lt;p&gt;O conhecimento adquirido fez efeito, e ela começou a ter sucesso nas negociações de salário, e até criou um tutorial maneiro, que ela nos cedeu, contendo &lt;strong&gt;diversos segredos MUITO VALIOSOS&lt;/strong&gt; descritos aqui abaixo.&lt;/p&gt;
&lt;h1&gt;TUTORIAL: Como chegar nos 10 mil de salário&lt;/h1&gt;
&lt;p&gt;Paula sempre teve como objetivo de vida o pragmatismo e a objetividade, e começou a pensar em formas de como ela poderia ganhar dinheiro, que poderiam ser aplicadas em qualquer carreira. Então ela bolou um &lt;strong&gt;plano que foi genial&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Na época, ela ganhava R$ 2.000 e queria um aumento. Na cabeça dela, R$ 500 de aumento seria EXCELENTE, e ela achava que seu chefe jamais aceitaria, mas mesmo assim tentou. Por acaso, o chefe aceitou a proposta e aumentou. Nesse ponto da história ela ficou feliz, mas olhando para o passado, ela enxergou muitos erros:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Ela teria que esperar muitos meses pra conseguir outra negociação.&lt;/li&gt;
&lt;li&gt;Ela negociou um valor muito baixo, com medo do gerente achar o valor alto.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;O que ela queria na verdade era um salário de R$ 10 mil, e isso continuou deixando ela insatisfeita, apesar de ter conseguido o aumento.&lt;/p&gt;
&lt;p&gt;Ela era imparável, e ainda queria ir atrás dos 5 dígitos, e foi aí que começou a estudar sobre negociação. Ela só começou a descobrir como negociar e como o mercado funcionava, quando começou a vender bugigangas na OLX, praticando a negociação com desconhecidos foi uma ótima forma de enxergar como chegar num valor que seja interessante pra ela. &lt;strong&gt;Paula viu que a vida prática é a melhor escola&lt;/strong&gt;, e que MBA nenhum ensinaria o que ele aprendeu com a prática.&lt;/p&gt;
&lt;p&gt;No processo de negociação, acabou descobrindo que ela nunca pode ser a primeira a falar um valor, pois no caso da primeira negociação, o gerente sabia que ela valia MUITO MAIS do que o valor que Paula tinha falado. Na cabeça do gerente, se ele pagasse R$ 6.500 ao Paula, ainda assim a empresa estaria com saúde financeira e qualquer valor abaixo disso seria possível da empresa pagar, mas &lt;strong&gt;Paula estragou essa oportunidade falando o valor primeiro&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Na prática, Paula aprendeu que para descobrir o valor que está na cabeça do gerente, ela sempre deveria jogar um &lt;strong&gt;valor absurdamente alto&lt;/strong&gt; durante a negociação, que ela tivesse a certeza que o gerente não toparia, pois ela &lt;strong&gt;NUNCA deve ser a parte da negociação que fala o valor&lt;/strong&gt;, é sempre a outra pessoa que deve falar, pois o valor da outra pessoa poderá ser maior do que o valor que ela tinha em mente.&lt;/p&gt;
&lt;p&gt;Mas isso ainda não tinha sido suficiente para que ela chegasse nos almejados R$ 10 mil. Paula então teve a sacada de mestre. Ela chegou ao seu gerente, Arnaldo, e perguntou: &lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;“Fala Arnaldo, tenho uma pergunta muito séria, eu queria que você me respondesse com toda sinceridade. Quais são EXATAMENTE os atributos e atividades que eu tenho que ter e fazer para que você me pague um salário de R$ 10 mil?”&lt;/li&gt;
&lt;/ul&gt;
&lt;blockquote&gt;
&lt;p&gt;Essa foi a jogada de mestre.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Arnaldo ficou sem escolha, pois ele teria que responder, e Paula saberia exatamente qual pessoa ela teria que se tornar para poder ganhar os R$ 10 mil. Ou seja, ela inverteu a lógica do processo e evitou que o gerente criasse impedimentos para a sua ambição.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Se Paula cumprisse os requisitos, o gerente não teria outra escolha além de pagar os R$ 10 mil.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Isso significa que seria fácil? &lt;strong&gt;NÃO&lt;/strong&gt;, mas significa que Paula teria o &lt;strong&gt;caminho EXATO&lt;/strong&gt; para conseguir chegar onde ela precisava para ganhar os R$ 10 mil, e é ai que mora o grande segredo. Como no vídeo do teste do jogo de basquete lá em cima, muitas vezes não conseguimos enxergar nossas fraquezas, e ter bom senso e humildade para entender que não somos perfeitos nos faz refletir sobre como podemos melhorar.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Não se trata somente de ambiente, ou trabalho duro sem inteligência, se trata da pessoa que você tem que se transformar para conseguir.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Significa que será rápido? &lt;strong&gt;DEPENDE&lt;/strong&gt;. Paula agora teria &lt;strong&gt;um caminho definido&lt;/strong&gt;, o que é mais importante que qualquer outra coisa, pois é mais importante você andar na direção certa a 50km/h, do que ir a 300km/h na direção completamente oposta.&lt;/p&gt;
&lt;p&gt;Paula conseguiu em 2 anos se tornar a pessoa que o gerente descreveu e não ganhou o aumento para R$ 10 mil, pois apesar de digna do merecimento &lt;strong&gt;o gerente não devia nada a ela&lt;/strong&gt;. O MUNDO NÃO DEVIA NADA A ELA, e isso foi chocante para ela.&lt;/p&gt;
&lt;p&gt;Paula ficou revoltada. Mas com o tempo percebeu que o que precisava era de mudar de ambiente, porque ali ela não tinha futuro e sabia que o valor que ele gerava era muito maior do que o que ela ganhava. Ao invés de xingar a empresa, ela canalisou a energia na sua contínua transformação em alguém melhor e em continuar gerando valor e procurando lugares e projetos que ela conseguisse mais valorização.&lt;/p&gt;
&lt;p&gt;Em pouco tempo, usando a mesma técnica de primeiro pegar o caminho e depois segui-lo, ela conseguiu chegar onde chegou, com &lt;strong&gt;organização&lt;/strong&gt;, &lt;strong&gt;paciência&lt;/strong&gt; e &lt;strong&gt;trabalho duro&lt;/strong&gt;. Isso a fez lembrar de uma frase que ela demorou bastante tempo para entender, mas que fez todo o sentido quando conseguiu conectar os pontos olhando sua carreira em retrospecto.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;“As pessoas superestimam o que fazem em 1 ano e subestimam o que podem fazer em uma década.” Tony Robbins.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;No Ano novo, Paula sempre observava as demais pessoas criando objetivos irreais, como por exemplo, achando que irão &lt;strong&gt;ficar magras em 1 ano sendo que ficaram as últimas duas décadas com hábitos alimentares ruins&lt;/strong&gt;. Ela sabia que a consistência e hábitos bons foram o que a fizeram suceder na carreira e atingir os objetivos, e via que as pessoas não tinham a visão do que a sua avó sempre a dizia &lt;strong&gt;“Você colhe o que planta”&lt;/strong&gt;, e o que ela mais presenciava nas pessoas ao seu redor era:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Queriam dar centavos e receber milhões.&lt;/li&gt;
&lt;li&gt;Queriam fazer pouco e receber muito.&lt;/li&gt;
&lt;li&gt;Queriam emagrecer 20kg sem dieta e sem aeróbico, no conforto do próprio sofá, só tomando o super shake magic 3000.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Nada como a vida para mostrar a realidade.
Certo dia em um churrasco organizado pelos seus amigos, ela teve um insight muito simples das regras da vida:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Quem leva schin não toma heineken.
Quem leva chuleta não come picanha.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Simples de entender né? Ainda tem gente que não enxerga e continuarão eternamente não enxergando o urso do Moonwalk. Repare que são os &lt;strong&gt;questionamentos e a curiosidade que movem o mundo&lt;/strong&gt;, e a pergunta martelada na cabeça da nossa protagonista: “Como faço pra gerar valor suficiente para que alguém queira me pagar R$ 10 mil por mês” foi responsável por:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;A levar a estudar o comportamento da riqueza;&lt;/li&gt;
&lt;li&gt;A levar a colocar em prática a arte da venda e da persuasão;&lt;/li&gt;
&lt;li&gt;A levar a pensar de forma mais objetiva e direta;&lt;/li&gt;
&lt;li&gt;A levar a se organizar, ser consistente e paciente;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Que em consequência a levou ao sucesso.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Não foi somente o desejo isolado, foi o esforço consciente e diário em busca do sonho dela que a fez chegar lá. &lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Qual o segredo de Paula? Ele seguia um mantra criado pelo fundador da Reativa Tecnologia, que serve para qualquer setor da vida:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;“Sucesso é o exercício contínuo do bom senso.” (Paulo Luan)&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;&lt;del&gt;SARCASM&lt;/del&gt; Essa frase já foi traduzida para mais de 80 idiomas, usada e citada por todos os coachs e gurus pelo mundo &lt;del&gt;END_SARCASM&lt;/del&gt;&lt;/p&gt;
&lt;p&gt;Se você achou que as dicas são furadas e que o texto não reflete a realidade, é provável que esse não seja o momento para você, e tudo bem também. :) Mas caso não seja esse o caso, e que você seja ambicioso e queira mudar de vida, quando você entender que &lt;strong&gt;se plantar limões não colherá jacas, seus sonhos não terão limites&lt;/strong&gt;.&lt;/p&gt;</content:encoded></item><item><title><![CDATA[Faculdade de TI é perda de tempo]]></title><description><![CDATA[Você se sente perdido? Ansioso? A faculdade parece que não te formou direito? As vagas exigem milhares de coisas e você se sente um bosta…]]></description><link>https://blog.reativa.dev/devo-fazer-faculdade-parte1/</link><guid isPermaLink="false">https://blog.reativa.dev/devo-fazer-faculdade-parte1/</guid><pubDate>Fri, 03 Jan 2020 00:00:00 GMT</pubDate><content:encoded>&lt;p&gt;&lt;span
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&lt;p&gt;Você se sente perdido? Ansioso? A faculdade parece que não te formou direito? As vagas exigem milhares de coisas e você se sente um bosta? &lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Eu tenho a solução!&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;É só você clicar na imagem abaixo (&lt;a href=&quot;https://bit.ly/guia-dev-autodidata&quot;&gt;ou aqui&lt;/a&gt;) e me pagar uma Pizza de Mussarela 🍕 eu te mostrarei um caminho organizado e 100% a prova de desculpas para você se tornar o melhor dev do mercado:&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://bit.ly/guia-dev-autodidata&quot;&gt;&lt;span
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&lt;p&gt;Você definitivamente não precisa de &lt;strong&gt;bootcamps CARÍSSIMOS&lt;/strong&gt; para se tornar um bom programador…&lt;/p&gt;
&lt;p&gt;Todo mundo imagina que uma carreira se inicia num curso superior, é o pensamento padrão. Mas na área de programação é diferente, estamos num momento que as empresas estão completamente desesperadas atrás de bons programadores, e elas não os encontram. &lt;/p&gt;
&lt;p&gt;Os programadores disponíveis no mercado são disputados brutalmente entre elas, acredite. Eu já formei diversas equipes de desenvolvedores para consultorias e startups, e sei exatamente o quão difícil é estar do lado da empresa.&lt;/p&gt;
&lt;p&gt;Já ofereci vagas de R$ 8.000,00 CLT para desenvolvedores plenos que tivessem conhecimentos específicos de Javascript, e demorei muito tempo para encontrar, e os devs que encontrei não tinham exatamente o fit para a vaga; outras vagas de R$9.900,00 CLT para sêniores tinham exatamente o mesmo problema.&lt;/p&gt;
&lt;p&gt;Tendo em vista essa dificuldade decidi focar a minha vida em ceder este conhecimento, pois: &lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Sei exatamente o que as empresas precisam;&lt;/li&gt;
&lt;li&gt;Sei exatamente como formar um programador para estas vagas que citei com cursos gratuitos na internet, e falarei tudo sem economizar nadinha nos nossos conteúdos;&lt;/li&gt;
&lt;li&gt;Em 3 anos de muita prática e trabalho duro, com os conhecimentos que te passarei aqui você estará apto para vagas de R$ 6.000,00 se você se aplicar verdadeiramente, sem a necessidade de um diploma de ensino superior.&lt;/li&gt;
&lt;li&gt;Você vai ter o conhecimento que adquiri durante mais de 10 anos da minha carreira de programação.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Atualmente a internet está inundada de informações, &lt;strong&gt;&lt;em&gt;o problema não é a falta de disponibilidade&lt;/em&gt;&lt;/strong&gt;, mas a filtragem do que é bom e ruim destes conteúdos. Qualquer tonto pode pegar uma câmera e falar um monte de abobrinha no YouTube, e isso gera dificuldade para separarmos o joio do trigo.&lt;/p&gt;
&lt;p&gt;Este problema eu resolvi para você. Todos os conteúdos que disponho em tudo o que a Reativa faz, passaram pelo meu filtro pessoal, tudo foi testado e aprovado por dezenas de programadores que conheço. Se você tem interesse em ter conteúdos para se tornar Sênior o mais rápido o possível, &lt;a href=&quot;http://bit.ly/form-reativa&quot;&gt;clique aqui que vou te mandar todas as informações&lt;/a&gt;.&lt;/p&gt;
&lt;p&gt;Muito se fala dos sucessos da carreira, mas pouco se fala do fracasso e das perdas de tempo que tivemos com coisas inúteis. O ensino superior é um desses tabus.&lt;/p&gt;
&lt;p&gt;Para exemplificar: &lt;/p&gt;
&lt;p&gt;Existe um conceito em startups chamado &lt;strong&gt;&lt;em&gt;MVP&lt;/em&gt;&lt;/strong&gt;, que consiste em criar um mínimo produto viável. Você lança algo incompleto no mercado, verifica se vai dar certo ou não, e só depois de testar o mercado e fazer dar certo que você investe dinheiro e cria o produto de verdade, o objetivo é &lt;strong&gt;&lt;em&gt;errar barato&lt;/em&gt;&lt;/strong&gt; e &lt;strong&gt;&lt;em&gt;corrigir o mais rápido o possível&lt;/em&gt;&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Tanto na vida quanto nos negócios, &lt;strong&gt;&lt;em&gt;errar não é algo que você escolhe&lt;/em&gt;&lt;/strong&gt;, é algo que &lt;strong&gt;&lt;em&gt;acontece&lt;/em&gt;&lt;/strong&gt;, e é a parte que eu considero mais importante do processo.&lt;/p&gt;
&lt;p&gt;Se você tiver que escolher entre errar ou acertar escolha sempre por ERRAR. Cada erro que você comete te deixa mais próximo, e mais consciente, do sucesso. Não devemos evitar os erros, pelo contrário, temos que nos expôr e estarmos sempre atentos a corrigir, mudar de rumo e acertar o mais rápido o possível.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;&lt;strong&gt;&lt;em&gt;O ensino superior não te deixa errar pequeno&lt;/em&gt;&lt;/strong&gt;, te coloca em um relacionamento abusivo de 5 anos pra você descobrir que aquela merda de profissão não era a sua paixão.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;No mundo do ensino superior as pessoas cometem o mesmo erro de quem investe milhões e criam um produto que fracassa, você realmente precisa investir 50 mil reais, gastar mais de 6 anos da sua vida pra descobrir que determinada área não é o que você gosta, ou que não tem vaga de emprego? presenciei pessoalmente dezenas de amigos e familiares estarem desempregados e com um diploma de engenharia de produção na parede.&lt;/p&gt;
&lt;p&gt;Você pode até discordar de mim em alguns pontos, eu não ligo, pois essa é só uma outra visão da realidade. Mas você NÃO precisa passar por essas humilhações pra entrar no ensino superior pra ter a falsa sensação de sucesso, porque acredite, existem outras alternativas.&lt;/p&gt;
&lt;p&gt;A história do João, um de meus colegas de trabalho, detalha bem como funciona fazer uma faculdade de TI e como ela nos prepara para o mercado de trabalho.&lt;/p&gt;
&lt;h1&gt;A história da uniesquina&lt;/h1&gt;
&lt;p&gt;João estava puto esses dias, falando do arrependimento de diversas escolhas que tomou na carreira como desenvolvedor, e que ninguém - inclusive os professores da uniesquina que ele estudou - o avisaram. Tudo começou quando o João pegou um super-desconto em um desses sites quaisquer de bolsa de faculdade, a mensalidade da engenharia da computação caiu de R$ 1.500 para R$ 850. JOÃO ESTAVA FELIZASSO.&lt;/p&gt;
&lt;p&gt;No início foi pura alegria, ambiente novo, pessoas novas, tudo ia bem. Mas João começou a reparar que a faculdade não era nada objetiva; ele já estava quase no terceiro ano e ainda não tinha aprendido quase nada de programação, ele tinha aprendido o básico de algoritmos mas metade da aula o professor usava pra falar da vida pessoal e mostrar fotos do filho que acabara de nascer.&lt;/p&gt;
&lt;p&gt;Era engraçado, que os professores eram super sacanas, ensinavam um conteúdo X e quando chegava na prova o cobravam coisas absurdamente diferentes dos conteúdos ensinados em aula. Era muito perceptível que o objetivo do professor era mais o de encher linguiça e sentir superior aos alunos do que ensinar de verdade o que o mercado precisava. Salvo por raras exceções de bons professores que sabiam que falavam, mas a maioria só tinham lido o conteúdo da aula em um livro e replicado sem ter conhecimento prático algum.&lt;/p&gt;
&lt;p&gt;Os colegas da sala faziam perguntas idiotas e redundantes, a falta de sono fazia o João querer agredir esses amiguinhos, os conflitos também aconteciam quando era necessário fazer os trabalhos em grupo:&lt;/p&gt;
&lt;p&gt;&lt;span
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    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Ele se sentia cada dia mais desmotivado, isso acabou levando João ao bar próximo da faculdade, o Gela-Guela. Os encontros no Gela-Guela ficavam cada vez mais frequentes do que a ida às aulas, ele estava mais motivado com a bebedeira e com as festas da faculdade do que com as matérias que &lt;strong&gt;&lt;em&gt;só o faziam perder tempo&lt;/em&gt;&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;A faculdade começava a ser levada com a barriga, copiava a prova dos amigos, assinava a lista de presença e metia fuga da aula. Qualquer coisa era mais empolgante do que estudar sociologia e português, matérias que por incrível que pareça compunham a grade de aulas, parecia surreal estudar aquela merda, quando a faculdade da qual ele tinha se inscrito era de computação.&lt;/p&gt;
&lt;p&gt;Após a reclamação de diversos alunos sobre as matérias irrelevantes, o boçal do diretor da faculdade dizia ser importante estudar matérias não correlacionadas ao curso pois isso o faria ser um profissional melhor, o fato é que no espaço limitado de tempo, &lt;strong&gt;&lt;em&gt;João acabou terminando a faculdade sem aprender programação&lt;/em&gt;&lt;/strong&gt; da forma certa.&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
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  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;É comum nas faculdades terem aulas de sociologia e português por exemplo, não faz sentido algum, eles querem preencher lacunas que ficaram de seu ensino básico, algo que teoricamente deveria ser aprendido num curso fora de lá. &lt;strong&gt;&lt;em&gt;Você se forma sem saber programar&lt;/em&gt;&lt;/strong&gt;, mas vai entender o “comportamento humano em função do meio e os processos que interligam os indivíduos em associações, grupos e instituições”. Bizarro, mas acontece na maioria dos cursos do ensino superior. &lt;/p&gt;
&lt;p&gt;Sendo pragmático, vão abordar um monte de matéria merda e &lt;strong&gt;&lt;em&gt;se você não for esperto e autodidata vai ser bem difícil ser um bom programador&lt;/em&gt;&lt;/strong&gt; e conseguir um emprego bom.&lt;/p&gt;
&lt;p&gt;Se você duvida do que estou falando pergunte pra qualquer pessoa que você conheça que tenha finalizado algum curso superior e efetivamente trabalhe na área de atuação:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Qual a porcentagem do que ela aprendeu na faculdade que ela efetivamente usa na vida real? &lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;&lt;strong&gt;&lt;em&gt;Você vai se surpreender com as respostas.&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;Voltando ao João, ao procurar as vagas no mercado de trabalho, ele descobriu que &lt;strong&gt;&lt;em&gt;não tinha 5% do que era requerido pelo mercado de trabalho&lt;/em&gt;&lt;/strong&gt;, e o mais cômico é que em nenhum deles era necessário ter conhecimentos de sociologia.&lt;/p&gt;
&lt;p&gt;João estava:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;R$ 51 mil reais mais pobre, decorrente das mensalidades que pagou, sem nem contar os custos de transporte e de horas de vida perdidas;&lt;/li&gt;
&lt;li&gt;Desgastado emocionalmente;&lt;/li&gt;
&lt;li&gt;Sem dinheiro;&lt;/li&gt;
&lt;li&gt;Sem os conhecimentos necessários para arrumar um bom emprego:&lt;/li&gt;
&lt;li&gt;João estava na bosta.&lt;/li&gt;
&lt;/ul&gt;
&lt;blockquote&gt;
&lt;p&gt;Essa história pode parecer exagerada, mas infelizmente se repete todos os anos, com milhares de pessoas que são mentoradas por essas merdas de faculdade.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Por professores que jamais colocaram um software de verdade em produção, que jamais tiveram que resolver um problema grave em um sistema que a cada minuto fora do ar fazia o cliente perder milhões de reais, que jamais realizaram nada no mundo real além de lerem alguns livrinhos, repetirem umas baboseiras e se sentirem super-heróis do conhecimento.&lt;/p&gt;
&lt;p&gt;Mais uma vez, existem exceções tantos nas instituições quanto no perfil de professores, mas quando existem são raríssimas de se encontrar e/ou caríssimas de se pagar. Posso discorrer por horas falando mal das faculdades, mas por ora, sendo objetivo, posso dizer que:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;O principal pecado das faculdades é a falta de objetividade.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Não tenho ódio pelas instituições de ensino superior, tampouco pelos professores envolvidos, sei que eles fazem o seu melhor. Acho importantíssimo o trabalho deles existirem e de oferecerem educação a quantidades astronômicas de pessoas. Pode parecer pretenção da minha parte em ter sido tão duro ao longo do texto, mas a minha raiva é pela ineficiência do sistema em criar bons programadores para o mercado, quando esse tinha que ser o único objetivo destas instituições.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Ao invés de focar na reclamação eu foquei em construir, gerar valor e ceder todo o meu conhecimento aqui nos conteúdos da Reativa, para que você fique consciente do problema e não perca tempo com caminhos que te levam para mais longe do seu potencial máximo.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
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  &gt;
    &lt;span
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&lt;p&gt;Desde muito jovem, temos que tomar decisões que podem definir completamente o nosso futuro. Somos forçados a prestar um vestibular difícil ou estudar coisas que sequer sabemos o motivo. De certa forma não temos como saber o que o futuro nos reserva, mas podemos aprender com os erros dos outros e ficarmos consciente dos problemas antes mesmo deles acontecerem. &lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Aprender com o erro alheio é a forma mais barata de se aprender.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;h2&gt;O caso do nutricionista gordo&lt;/h2&gt;
&lt;p&gt;Diego gorducho era um outro camarada que conheci em um dos projetos que trabalhei. Tinha graves problemas de peso, afetando sua mobilidade a ponto de mal conseguir andar. Apesar disto, Diegão não conseguia conter os péssimos hábitos que mantinha, por sorte e pelo ambiente masculino-hostil que ele trabalhava, sempre tivera amigos que o fizeram bullying, uma ferramenta maldosa e que claramente não concordo, mas que o empurrou em direção ao combate suas fragilidades.&lt;/p&gt;
&lt;p&gt;Existe um conceito matemático chamado &lt;a href=&quot;https://pt.wikipedia.org/wiki/Ponto_de_inflex%C3%A3o&quot;&gt;ponto de inflexão&lt;/a&gt;, que é um ponto sobre uma curva na qual a operação muda de sinal, indo do negativo ao positivo. &lt;a href=&quot;https://www.amazon.com.br/Ponto-inflex%C3%A3o-Fl%C3%A1vio-Augusto-Silva/dp/8593156835&quot;&gt;Flávio Augusto&lt;/a&gt; a define como:&lt;/p&gt;
&lt;p&gt;&lt;em&gt;as decisões que tem o poder de mudar o rumo e o roteiro de nossas vidas.&lt;/em&gt;&lt;/p&gt;
&lt;p&gt; &lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
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&lt;p&gt;Dentre as zoações e sacanagens, os amigos do Diego, falaram uma frase que soou bastante seca e dura mas mudou a vida dele para todo o sempre: &lt;em&gt;“Diegão, se você perde a batalha pra batata frita, com quem você empata?”&lt;/em&gt;&lt;/p&gt;
&lt;p&gt;Aquele foi um dos pontos de inflexão mais importantes da vida do nosso amigo, o fez mudar de hábitos e consequentemente o levou ao caminho do bem estar na vida. Sempre que fraquejava ele repetia o mantra: &lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;”&lt;strong&gt;Resignação&lt;/strong&gt; para aceitar o que não pode ser mudado, &lt;strong&gt;Força de vontade&lt;/strong&gt; para mudar aquilo que pode ser mudado e &lt;strong&gt;Sabedoria&lt;/strong&gt; para distinguir uma coisa da outra”.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Diego sabia que &lt;strong&gt;&lt;em&gt;o caminho que o levava da virtude ao vício era muito menor que o caminho do vício a virtude&lt;/em&gt;&lt;/strong&gt;, e foi uma das primeiras pessoas que eu presenciei que percebeu que não existiam fórmulas mágicas para o sucesso, além de &lt;strong&gt;trabalho duro&lt;/strong&gt;, &lt;strong&gt;consistência&lt;/strong&gt; e &lt;strong&gt;tempo&lt;/strong&gt;. &lt;/p&gt;
&lt;p&gt;Filósofo e muito focado, chegou a tatuar em suas costas: &lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;“Procura satisfação de veres morrer os teus vícios antes de ti”&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Nunca senti tanto orgulho daquele, literal e carinhosamente, grande homem.&lt;/p&gt;
&lt;p&gt;Um dos fatos que me chamaram a atenção na história do Diegão, é que o início da batalha dele contra o peso ele foi até um profissional de reeducação alimentar, o nutricionista Lucas, que por um acaso estava tão acima do peso quanto ele. O que a princípio para as pessoas, pode invalidar o seu discurso somente por sua estética fora do padrão do que suas teorias de magreza pregam, que ocasiona questionamentos: “como ele quer que eu seja magro se ele também é gordo?”&lt;/p&gt;
&lt;p&gt;Isso abre margem para uma outra discussão, a do preconceito baseado na imagem, de seguir o padrão social imposto como “bonito”. Na história, Diego mudou porque ele estava morrendo, e não porque queria ser aceito pelos amigos.&lt;/p&gt;
&lt;p&gt;Existem casos, onde a obesidade ainda é pregada como forma de comportamento, como se as pessoas fossem gordas porque não têm vergonha na cara, não se esforçam e não se dedicam a emagrecer, entenda que não é esse o caso da história que acabei de contar, Diegão era obeso pelos hábitos ruins e não pelos fatores supracitados.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;O problema é quando tentam relativizar a preguiça em cima de qualquer discurso.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;A vida é muito mais complexa do que só ter força de vontade e resiliência, no caso do nutricionista gordo, podem existir inúmeras variáveis que o fazem estar acima do peso, metabolismo extremamente ruim, desequilíbrio emocional que necessita de acompanhamento psiquiátrico, genética desfavorável, temos que ser flexíveis em entender que a vida é bem mais complexa, pois, claramente existem casos onde a pessoa faz de tudo e ainda assim não consegue, &lt;strong&gt;a vida não é justa, e nem tão bonita quanto geral prega&lt;/strong&gt;.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;O que temos em comum é que se algo é difícil, é difícil pra todo mundo, o que faz da história de Diego ser ainda mais admirável.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;O objeto da discussão é que a antifragilidade e capacidade de superação do nosso protagonista foram decisivas em mudar a vida dele, e que se você quiser, você tem que se esforçar muito e ainda correr o risco de não conseguir. Muita gente desiste só de ouvir o que acabei de dizer, se algo é difícil eles nem tentam, e essa é a magia! Se eles desistem sobra mais espaço para você chegar ao topo.&lt;/p&gt;
&lt;p&gt;Voltando ao nutri gordinho, isso me fez questionar, será que os resultados que as pessoas têm, são diretamente relacionados aos seus hábitos? &lt;strong&gt;Na maioria dos casos sim!&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;A sociedade é baseada em pré-conceber a relevância de opiniões baseado nos resultados, você ouviria conselhos:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;De um programador que usa windows? (brinks)&lt;/li&gt;
&lt;li&gt;De um dentista com o dente podre?&lt;/li&gt;
&lt;li&gt;De um psicólogo surtado agressor de mulheres?&lt;/li&gt;
&lt;li&gt;De um coach que dá conselhos de riqueza e vai embora de Pálio 1997?&lt;/li&gt;
&lt;/ul&gt;
&lt;blockquote&gt;
&lt;p&gt;Então porque aceita na moralzinha pagar 50 mil reais para ficar ouvindo por 5 fucking anos baboseira de professor que nunca realizou nada no mundo real?&lt;/p&gt;
&lt;/blockquote&gt;
&lt;h2&gt;Os professores de palco&lt;/h2&gt;
&lt;p&gt;Você acha que os professores do curso de administração administram alguma coisa? Se você fosse ele, você iria escolher:&lt;/p&gt;
&lt;div class=&quot;gatsby-highlight&quot; data-language=&quot;text&quot;&gt;&lt;pre style=&quot;counter-reset: linenumber NaN&quot; class=&quot;language-text line-numbers&quot;&gt;&lt;code class=&quot;language-text&quot;&gt;(A)   Administrar uma empresa foda e ganhar milhões
(B)   Dar aula numa faculdade e ganhar 7 mil no mês.&lt;/code&gt;&lt;span aria-hidden=&quot;true&quot; class=&quot;line-numbers-rows&quot; style=&quot;white-space: normal; width: auto; left: 0;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/pre&gt;&lt;/div&gt;
&lt;p&gt;Acho bem improvável ser a opção B, eu nunca vi um empresário nível Flávio augusto dando aula Full Time numa uniesquina.&lt;/p&gt;
&lt;p&gt;Atente-se que não estou colocando &lt;strong&gt;TODOS&lt;/strong&gt; os professores no mesmo barco, até porque &lt;strong&gt;a classe de professores é muito prejudicada&lt;/strong&gt;, muitas vezes ganham salários baixos e são completamente capados por ordens vindas “de cima”, o problema é tão complexo quanto os que eu citei do metabolismo do nutri-fofo. Estou isolando &lt;strong&gt;apenas&lt;/strong&gt; os professores que sacaneiam propositalmente por não se atualizarem, os que tem medo de inovar, os que não trasmitem o conhecimento com paixão, os que leram o último livro em 1989 e ainda mantém a mesma merda de aula para toda turma que vem e vai, aquele que tem PHd no currículo mas não sabe ligar um projetor. &lt;strong&gt;Lembrando também que o contexto do texto é isolado para a área de tecnologia, da qual eu presenciei pessoalmente.&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;Algo que sempre me intrigou nesses professores-de-palco é que se nem mesmo eles conseguiram lutar na selva do mercado, se escondendo atrás de empregos públicos e/ou que não exigem dificuldade e inovação a níveis extremos, como é que estarão aptos a opinar ou te mentorar para o processo da administração da vida real?&lt;/p&gt;
&lt;p&gt;É muito mais válido, rápido e barato, quebrar a cara por conta própria e ser responsivo aos problemas da vida do que ouvir conselhos de outras pessoas não realizadoras que te dão dicas genéricas e não práticas da vida.&lt;/p&gt;
&lt;p&gt;Foque em ouvir quem construiu algo de verdade, mas é bastante improvável que você vá ficar rodeado de bilionários e programadores se você mora em Pirangabinha do Bom Jesus por exemplo, é por isso que os livros e a internet o ajudarão a se rodear das pessoas que tem os mesmos objetivos que você. &lt;/p&gt;
&lt;p&gt;Por esse motivo &lt;a href=&quot;https://reativa.dev/&quot;&gt;a Reativa&lt;/a&gt; existe, para unir as pessoas que tem interesse em crescer como profissional, ajudando os devs iniciantes a chegarem na &lt;a href=&quot;http://bit.ly/form-reativa&quot;&gt;senioridade no menor tempo o possível&lt;/a&gt; usando apenas a internet e sua vontade em crescer na vida, aqui nós usamos a prática e a experimentação em primeiro lugar!&lt;/p&gt;
&lt;p&gt;Falando nisso, limitar a experimentação é outro pecado gravíssimo do ensino superior e da educação base como geral. A educação tradicional está falida, ensinamos as pessoas da mesma maneira durante os últimos 100 anos e, como crescemos nesse sistema, achamos que é normal, mas é uma loucura. É sério que passar 12 anos da vida sentado do mesmo modo que as crianças sentavam em 1920 é o melhor método?&lt;/p&gt;
&lt;h2&gt;Faculdade é perda de dinheiro?&lt;/h2&gt;
&lt;p&gt;Pensa comigo, analisando o modelo de negócios das faculdades, tanto públicas quanto privadas, faz muito sentido te manter o máximo de tempo o possível matriculado como aluno, as privadas para terem fluxo de caixa com as mensalidades pagas por você, as públicas para manterem o status quo e a necessidade de se ter os funcionários públicos.&lt;/p&gt;
&lt;p&gt;Talvez você já tenha reparado que desde o ensino básico na escola eles te ensinam um monte de baboseira, que você aprendia por um ouvido e soltava pelo outro, isso sempre aconteceu, e se perdura no ensino superior, até os dias de hoje. E nesse caso não é tanto culpa do professor, mas da estrutura de ensino existente, as ordens sempre vêm de cima e capam cada vez mais a capacidade do professor inovar.&lt;/p&gt;
&lt;p&gt;Você lembra das fórmulas matemáticas que você aprendeu na sétima série do ensino fundamental? Se eu te perguntasse então como fazer escalonamento de matrizes, ou que eu dissesse que dois segmentos nulos são sempre equipolentes na teoria dos vetores você concordaria? Você também explicaria de cabeça a diferença exata de anáfora e catáfora e quais são as regras dos usos de Pronomes relativos e conjunções?&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;&lt;em&gt;Tudo que você não pratica, você esquece.&lt;/em&gt;&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Do lado contrário, tudo que você &lt;strong&gt;pratica&lt;/strong&gt; você &lt;strong&gt;detem&lt;/strong&gt; o conhecimento. As regras gramaticais de linguagem ou a forma de fazer cálculos está implícita na sua cabeça, você não sabe exatamente a diferença das perguntas do parágrafo anterior, mas quando escreve uma redação ou faz uma conta, utiliza dos conhecimentos empíricos, mesmo sem saber toda a teoria ou nomes bonitos por trás delas.&lt;/p&gt;
&lt;h2&gt;Foque na prática&lt;/h2&gt;
&lt;p&gt;A média de tempo de uma faculdade de graduação varia entre &lt;strong&gt;3.600 à 4.000 horas&lt;/strong&gt; , qual você acha que vale mais? 4000 horas programando, ou 4000 horas numa faculdade?&lt;/p&gt;
&lt;p&gt;Agora imagine que você tenha que escolher entre dois lutadores:&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Lutador A:&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;span
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    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 100%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
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        alt=&quot;lutador a&quot;
        title=&quot;lutador a&quot;
        src=&quot;/static/4585478051d4c0134adc1bb4bd4d8689/8c2ab/lutador_a.png&quot;
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  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Estudou 4000 horas em uma academia tradicional, 80% do tempo foi sentado numa cadeirinha ouvindo conselhos de outros lutadores que nunca lutaram de verdade, mas assistiram várias aulas de luta, viu um pouquinho de luta prática no curso, mas sem encostar no amiguinho, era só pra treinar as movimentações. Nunca lutou de verdade, mas tem um quadro bem bonito na parede do apartamento com móveis planejados, que diz que ele fez um curso de 4000 horas sobre lutas, uma uniesquina CERTIFICOU que ele sabe tudo sobre lutas. &lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Lutador B:&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
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  &gt;
    &lt;span
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  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;lutador b&quot;
        title=&quot;lutador b&quot;
        src=&quot;/static/78bb9db568f369e898f4e841cfc72bb0/0a064/lutador_b.png&quot;
        srcset=&quot;/static/78bb9db568f369e898f4e841cfc72bb0/00d96/lutador_b.png 148w,
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      /&gt;
  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Criado pela vida, passou as 4000 horas brigando em porta de bar risca faca, já apanhou de paulada, de faca, já brigou com gente mais forte, apanhou de bando, foi em coma e voltou, quebrou o nariz 7 vezes, &lt;strong&gt;aprendeu tudo sozinho&lt;/strong&gt; na marra, &lt;strong&gt;na prática&lt;/strong&gt; , a mão parece uma pedra de tão dura de tanto soco que já deu em seus oponentes.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Você tem que escolher entre um dos dois para compor o seu time e te proteger na hora da treta, qual você escolhe?&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;Coloque o mesmo ceńario, um programador teórico de uniesquina, ou um programador forjado na prática, qual você acha que eu escolheria na posição para compor minha equipe? O autodidata brabão ou o engomadinho da uniesquina?&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;&lt;em&gt;Foque a sua vida em estudar essas 4.000 horas em coisas que sejam úteis de verdade.&lt;/em&gt;&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Lembro até hoje de um garoto que contratei, tinha uns 18 anos, era gamer, não tinha faculdade, me disse que tinha aprendido inglês aos 11 anos de idade sozinho, e que programação tinha sido a mesma coisa, somente lendo tutorial e fazendo tudo na prática. Adivinha se meus olhos não brilharam?&lt;/p&gt;
&lt;p&gt;Lembre-se disso:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;&lt;em&gt;As empresas contratam potenciais. Eles são baratos, e a longo prazo o melhor investimento&lt;/em&gt;&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Se esse muleque me pedisse R$3000 de salário sem experiência, ainda assim eu o contrataria. Quem você conhece que aprendeu inglês aos 11 anos e programação sozinho? O problema é que a maioria não sabe o potencial de valor que eles representam ou sequer estão conscientes sobre estes problemas, de qualquer forma agora você sabe e ainda bem que eu estou aqui pra te ajudar.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Então eu devo chutar o balde, abandonar a faculdade e investir somente em cursos online????&lt;/p&gt;
&lt;/blockquote&gt;
&lt;h2&gt;Antítese dos meus argumentos&lt;/h2&gt;
&lt;p&gt;O Fábio Akita é um dos desenvolvedores / empreendedores que eu mais respeito. Recomendo a todos que assistam os &lt;a href=&quot;https://www.youtube.com/user/AkitaOnRails&quot;&gt;vídeos&lt;/a&gt; e &lt;a href=&quot;https://www.akitaonrails.com/&quot;&gt;blog posts&lt;/a&gt; dele, a quantidade de conhecimentos que vocẽ absorver é absurdamente grande.&lt;/p&gt;
&lt;p&gt;Um vídeo do Akita em específico, fala sobre a importância das faculdades na visão dele:&lt;/p&gt;
&lt;p&gt;&lt;div class=&quot;gatsby-resp-iframe-wrapper&quot; style=&quot;padding-bottom: 56.49999999999999%; position: relative; height: 0; overflow: hidden; margin-bottom: 1.0725rem&quot; &gt; &lt;iframe src=&quot;https://www.youtube.com/embed/XWVcF7BoCSc?feature=oembed&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen style=&quot; position: absolute; top: 0; left: 0; width: 100%; height: 100%; &quot;&gt;&lt;/iframe&gt; &lt;/div&gt;&lt;/p&gt;
&lt;p&gt;Eu recomendo que você assista, ele basicamente fala que a base que a faculdade te proporciona vai te fazer aprender melhor no futuro.&lt;/p&gt;
&lt;p&gt;Eu sou a favor de outra abordagem, o &lt;a href=&quot;https://en.wikipedia.org/wiki/Pareto_principle&quot;&gt;princípio de pareto&lt;/a&gt; diz que 20% dos esforços são responsáveis por 80% dos resultados, eu acredito que você deve aprender as coisas por demanda:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Entrar no mercado de trabalho no menor tempo o possível;&lt;/li&gt;
&lt;li&gt;Observar como as coisas funcionam; &lt;/li&gt;
&lt;li&gt;Focar em primeiro não morrer de fome, pra depois aprender conceitos mais profundos de computação;&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Sério mesmo que eu preciso aprender a fazer uma árvore binária recursiva e calcular complexidade assintótica de algoritmos e entender como funciona a estrutura de dados em grafo do GIT, antes de arrumar um emprego que vá pagar as minhas contas pra eu poder sobreviver?&lt;/p&gt;
&lt;p&gt;Para a minha realidade de fudido que se formou em escola pública de merda e não tinha chance alguma de passar em nenhum vestibular, queimar 4 anos de cursinho e mais 5 de faculdade não era uma opção.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Se a microlins tivesse um vestibular eu não passaria.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Cada um tem uma prioridade, as coisas que ensinam na faculdade são importantes em algum momento da carreira, mas não é no momento que você está passando fome e trabalhando de telemarketing pra conseguir pagar o ônibus e uma coxinha com guaraná para sobreviver.&lt;/p&gt;
&lt;p&gt;Outro vídeo recomendadíssimo é do &lt;a href=&quot;https://www.youtube.com/channel/UClFbl7Rh9N17nTT1ppWn2MQ&quot;&gt;Neto Marin&lt;/a&gt;, que fala com muita elegância e abrangência o assunto: &lt;/p&gt;
&lt;p&gt;&lt;div class=&quot;gatsby-resp-iframe-wrapper&quot; style=&quot;padding-bottom: 56.49999999999999%; position: relative; height: 0; overflow: hidden; margin-bottom: 1.0725rem&quot; &gt; &lt;iframe src=&quot;https://www.youtube.com/embed/t0TkXuxGjqg?feature=oembed&quot; frameborder=&quot;0&quot; allow=&quot;accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture&quot; allowfullscreen style=&quot; position: absolute; top: 0; left: 0; width: 100%; height: 100%; &quot;&gt;&lt;/iframe&gt; &lt;/div&gt;&lt;/p&gt;
&lt;p&gt;Se quiser ir devagar e pelo caminho dito como seguro e conservador, te dou toda a coragem para passar 3 anos de cursinho e mais 5 de faculdade. Vá feliz pintar a cara no trote e pensar que esse é o momento mais importante da sua vida. &lt;/p&gt;
&lt;p&gt;Mas se quiser encarar a realidade e ir pelo caminho mais efetivo e mais turbinado o possível, venha com a gente. Na sua vida é sempre você mesmo que faz conscientemente as decisões, e te desejo sucesso em ambos os casos.&lt;/p&gt;</content:encoded></item><item><title><![CDATA[As empresas estão desesperadas por programadores]]></title><description><![CDATA[Clique nas imagens caso queira ir para a notícia original:         Existia uma época quando a revolução industrial estava a plenos pulmões…]]></description><link>https://blog.reativa.dev/empresas-desesperadas/</link><guid isPermaLink="false">https://blog.reativa.dev/empresas-desesperadas/</guid><pubDate>Thu, 02 Jan 2020 00:00:00 GMT</pubDate><content:encoded>&lt;p&gt;&lt;span
      class=&quot;gatsby-resp-image-wrapper&quot;
      style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;
    &gt;
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    class=&quot;gatsby-resp-image-link&quot;
    href=&quot;/static/9493710db414f65f9e029a439dd781e9/9d22c/empresas_desesperadas.png&quot;
    style=&quot;display: block&quot;
    target=&quot;_blank&quot;
    rel=&quot;noopener&quot;
  &gt;
    &lt;span
    class=&quot;gatsby-resp-image-background-image&quot;
    style=&quot;padding-bottom: 100%; position: relative; bottom: 0; left: 0; background-image: url(&apos;data:image/png;base64,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&apos;); background-size: cover; display: block;&quot;
  &gt;&lt;/span&gt;
  &lt;img
        class=&quot;gatsby-resp-image-image&quot;
        alt=&quot;empresas desesperadas&quot;
        title=&quot;empresas desesperadas&quot;
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  &lt;/a&gt;
    &lt;/span&gt;&lt;/p&gt;
&lt;p&gt;Clique nas imagens caso queira ir para a notícia original:&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://economia.estadao.com.br/noticias/geral,em-um-pais-com-desemprego-de-13-sobram-vagas-na-area-de-tecnologia,70002816007&quot; target=&quot;_blank&quot;&gt;&lt;span class=&quot;gatsby-resp-image-wrapper&quot; style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;&gt;
      &lt;span class=&quot;gatsby-resp-image-background-image&quot; style=&quot;padding-bottom: 67.03296703296702%; position: relative; bottom: 0; left: 0; background-image: url(&amp;apos;data:image/png;base64,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&amp;apos;); background-size: cover; display: block;&quot;&gt;&lt;/span&gt;
  &lt;img class=&quot;gatsby-resp-image-image&quot; alt=&quot;Em um pa&amp;#xED;s com desemprego de 13%, sobram vagas na &amp;#xE1;rea de tecnologia&quot; title=&quot;Em um pa&amp;#xED;s com desemprego de 13%, sobram vagas na &amp;#xE1;rea de tecnologia&quot; src=&quot;/static/36dc1a1a2ad7676e2bdba9f378636a4e/799d3/1.png&quot; srcset=&quot;/static/36dc1a1a2ad7676e2bdba9f378636a4e/00d96/1.png 148w,
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    &lt;/span&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://g1.globo.com/especial-publicitario/digital-house/noticia/onde-nao-falta-emprego-procura-se-programadores.ghtml&quot; target=&quot;_blank&quot;&gt;&lt;span class=&quot;gatsby-resp-image-wrapper&quot; style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;&gt;
      &lt;span class=&quot;gatsby-resp-image-background-image&quot; style=&quot;padding-bottom: 45.69640062597809%; position: relative; bottom: 0; left: 0; background-image: url(&amp;apos;data:image/png;base64,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&amp;apos;); background-size: cover; display: block;&quot;&gt;&lt;/span&gt;
  &lt;img class=&quot;gatsby-resp-image-image&quot; alt=&quot;Onde n&amp;#xE3;o falta emprego: procura-se programadores
De ind&amp;#xFA;strias a com&amp;#xE9;rcios na internet, todo tipo de empresa hoje precisa de um programador para ser digital&quot; title=&quot;Onde n&amp;#xE3;o falta emprego: procura-se programadores
De ind&amp;#xFA;strias a com&amp;#xE9;rcios na internet, todo tipo de empresa hoje precisa de um programador para ser digital&quot; src=&quot;/static/cf95d7dbc0322c5f249d180dd0729e15/799d3/2.png&quot; srcset=&quot;/static/cf95d7dbc0322c5f249d180dd0729e15/00d96/2.png 148w,
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/static/cf95d7dbc0322c5f249d180dd0729e15/11e34/2.png 639w&quot; sizes=&quot;(max-width: 590px) 100vw, 590px&quot; loading=&quot;lazy&quot;&gt;
    &lt;/span&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://canaltech.com.br/empregos/milhares-de-vagas-em-ti-nao-estao-sendo-preenchidas-por-falta-de-qualificacao-149453/&quot; target=&quot;_blank&quot;&gt;&lt;span class=&quot;gatsby-resp-image-wrapper&quot; style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;&gt;
      &lt;span class=&quot;gatsby-resp-image-background-image&quot; style=&quot;padding-bottom: 68.08846761453397%; position: relative; bottom: 0; left: 0; background-image: url(&amp;apos;data:image/png;base64,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&amp;apos;); background-size: cover; display: block;&quot;&gt;&lt;/span&gt;
  &lt;img class=&quot;gatsby-resp-image-image&quot; alt=&quot;Milhares de vagas em TI n&amp;#xE3;o est&amp;#xE3;o sendo preenchidas por falta de qualifica&amp;#xE7;&amp;#xE3;o
&quot; title=&quot;Milhares de vagas em TI n&amp;#xE3;o est&amp;#xE3;o sendo preenchidas por falta de qualifica&amp;#xE7;&amp;#xE3;o
&quot; src=&quot;/static/10ff8b0c1464c90614a600e0d4ea030a/799d3/3.png&quot; srcset=&quot;/static/10ff8b0c1464c90614a600e0d4ea030a/00d96/3.png 148w,
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/static/10ff8b0c1464c90614a600e0d4ea030a/799d3/3.png 590w,
/static/10ff8b0c1464c90614a600e0d4ea030a/f64c6/3.png 633w&quot; sizes=&quot;(max-width: 590px) 100vw, 590px&quot; loading=&quot;lazy&quot;&gt;
    &lt;/span&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://exame.abril.com.br/carreira/este-tipo-de-desenvolvedor-e-raro-no-brasil-e-por-isso-ganha-ate-r-15-mil/&quot; target=&quot;_blank&quot;&gt;&lt;span class=&quot;gatsby-resp-image-wrapper&quot; style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;&gt;
      &lt;span class=&quot;gatsby-resp-image-background-image&quot; style=&quot;padding-bottom: 44.801223241590215%; position: relative; bottom: 0; left: 0; background-image: url(&amp;apos;data:image/png;base64,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&amp;apos;); background-size: cover; display: block;&quot;&gt;&lt;/span&gt;
  &lt;img class=&quot;gatsby-resp-image-image&quot; alt=&quot;Este tipo de desenvolvedor &amp;#xE9; raro no Brasil e por isso ganha at&amp;#xE9; R$ 15 mil Uma das carreiras mais quentes atualmente na &amp;#xE1;rea de desenvolvimento tem atra&amp;#xED;do profissionais pelos altos sal&amp;#xE1;rios e possibilidades de trabalho remoto&quot; title=&quot;Este tipo de desenvolvedor &amp;#xE9; raro no Brasil e por isso ganha at&amp;#xE9; R$ 15 mil Uma das carreiras mais quentes atualmente na &amp;#xE1;rea de desenvolvimento tem atra&amp;#xED;do profissionais pelos altos sal&amp;#xE1;rios e possibilidades de trabalho remoto&quot; src=&quot;/static/3b3f73e7e42453b6e0192aac80fb92a8/799d3/5.png&quot; srcset=&quot;/static/3b3f73e7e42453b6e0192aac80fb92a8/00d96/5.png 148w,
/static/3b3f73e7e42453b6e0192aac80fb92a8/0b23c/5.png 295w,
/static/3b3f73e7e42453b6e0192aac80fb92a8/799d3/5.png 590w,
/static/3b3f73e7e42453b6e0192aac80fb92a8/ebbc9/5.png 654w&quot; sizes=&quot;(max-width: 590px) 100vw, 590px&quot; loading=&quot;lazy&quot;&gt;
    &lt;/span&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://valorinveste.globo.com/objetivo/empreenda-se/noticia/2019/10/29/escassez-de-profissionais-eleva-salarios-de-desenvolvedores-ios-e-android-a-mais-de-r-9500.ghtml&quot; target=&quot;_blank&quot;&gt;&lt;span class=&quot;gatsby-resp-image-wrapper&quot; style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;&gt;
      &lt;span class=&quot;gatsby-resp-image-background-image&quot; style=&quot;padding-bottom: 56.58307210031348%; position: relative; bottom: 0; left: 0; background-image: url(&amp;apos;data:image/png;base64,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&amp;apos;); background-size: cover; display: block;&quot;&gt;&lt;/span&gt;
  &lt;img class=&quot;gatsby-resp-image-image&quot; alt=&quot;Escassez de profissionais eleva sal&amp;#xE1;rios de desenvolvedores iOs e Android a mais de R$ 9.500
Pesquisa da plataforma de recrutamento trampos.co revela que falta de especialistas em tecnologia da informa&amp;#xE7;&amp;#xE3;o est&amp;#xE1; fazendo ganhos na &amp;#xE1;rea subirem em ritmo acelerado&quot; title=&quot;Escassez de profissionais eleva sal&amp;#xE1;rios de desenvolvedores iOs e Android a mais de R$ 9.500
Pesquisa da plataforma de recrutamento trampos.co revela que falta de especialistas em tecnologia da informa&amp;#xE7;&amp;#xE3;o est&amp;#xE1; fazendo ganhos na &amp;#xE1;rea subirem em ritmo acelerado&quot; src=&quot;/static/268df1f60e0403734aff6cdc887a7b32/799d3/6.png&quot; srcset=&quot;/static/268df1f60e0403734aff6cdc887a7b32/00d96/6.png 148w,
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/static/268df1f60e0403734aff6cdc887a7b32/799d3/6.png 590w,
/static/268df1f60e0403734aff6cdc887a7b32/95f4e/6.png 638w&quot; sizes=&quot;(max-width: 590px) 100vw, 590px&quot; loading=&quot;lazy&quot;&gt;
    &lt;/span&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://g1.globo.com/especial-publicitario/digital-house/noticia/ceos-das-maiores-startups-do-brasil-estao-a-procura-de-programadores.ghtml&quot; target=&quot;_blank&quot;&gt;&lt;span class=&quot;gatsby-resp-image-wrapper&quot; style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;&gt;
      &lt;span class=&quot;gatsby-resp-image-background-image&quot; style=&quot;padding-bottom: 50.396196513470684%; position: relative; bottom: 0; left: 0; background-image: url(&amp;apos;data:image/png;base64,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&amp;apos;); background-size: cover; display: block;&quot;&gt;&lt;/span&gt;
  &lt;img class=&quot;gatsby-resp-image-image&quot; alt=&quot;CEO&amp;#xB4;s das maiores startups do Brasil est&amp;#xE3;o &amp;#xE0; procura de programadores Falta de profissionais qualificados &amp;#xE9; um dos principais gargalos para crescimento de empresas de tecnologia no pa&amp;#xED;s. Veja o que pensam os CEO&amp;#xB4;s dessas empresas&quot; title=&quot;CEO&amp;#xB4;s das maiores startups do Brasil est&amp;#xE3;o &amp;#xE0; procura de programadores Falta de profissionais qualificados &amp;#xE9; um dos principais gargalos para crescimento de empresas de tecnologia no pa&amp;#xED;s. Veja o que pensam os CEO&amp;#xB4;s dessas empresas&quot; src=&quot;/static/9ea59a1e1ce46a749ad3941b10091eb9/799d3/7.png&quot; srcset=&quot;/static/9ea59a1e1ce46a749ad3941b10091eb9/00d96/7.png 148w,
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/static/9ea59a1e1ce46a749ad3941b10091eb9/e2052/7.png 631w&quot; sizes=&quot;(max-width: 590px) 100vw, 590px&quot; loading=&quot;lazy&quot;&gt;
    &lt;/span&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;http://outline.com/https://oglobo.globo.com/economia/emprego/mercado-de-tecnologia-tem-deficit-de-24-mil-profissionais-por-ano-24170633&quot; target=&quot;_blank&quot;&gt;&lt;span class=&quot;gatsby-resp-image-wrapper&quot; style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;&gt;
      &lt;span class=&quot;gatsby-resp-image-background-image&quot; style=&quot;padding-bottom: 55.08607198748044%; position: relative; bottom: 0; left: 0; background-image: url(&amp;apos;data:image/png;base64,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&amp;apos;); background-size: cover; display: block;&quot;&gt;&lt;/span&gt;
  &lt;img class=&quot;gatsby-resp-image-image&quot; alt=&quot;Mercado de tecnologia tem d&amp;#xE9;ficit de 24 mil profissionais por ano
&quot; title=&quot;Mercado de tecnologia tem d&amp;#xE9;ficit de 24 mil profissionais por ano
&quot; src=&quot;/static/dcf24fab0cdffa4b86072b09e3181b6e/799d3/8.png&quot; srcset=&quot;/static/dcf24fab0cdffa4b86072b09e3181b6e/00d96/8.png 148w,
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/static/dcf24fab0cdffa4b86072b09e3181b6e/799d3/8.png 590w,
/static/dcf24fab0cdffa4b86072b09e3181b6e/11e34/8.png 639w&quot; sizes=&quot;(max-width: 590px) 100vw, 590px&quot; loading=&quot;lazy&quot;&gt;
    &lt;/span&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a href=&quot;https://g1.globo.com/jornal-nacional/noticia/2019/04/02/startups-tem-cinco-mil-vagas-abertas-no-pais-a-espera-de-trabalhadores.ghtml&quot; target=&quot;_blank&quot;&gt;&lt;span class=&quot;gatsby-resp-image-wrapper&quot; style=&quot;position: relative; display: block; margin-left: auto; margin-right: auto;  max-width: 590px;&quot;&gt;
      &lt;span class=&quot;gatsby-resp-image-background-image&quot; style=&quot;padding-bottom: 50.61162079510704%; position: relative; bottom: 0; left: 0; background-image: url(&amp;apos;data:image/png;base64,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&amp;apos;); background-size: cover; display: block;&quot;&gt;&lt;/span&gt;
  &lt;img class=&quot;gatsby-resp-image-image&quot; alt=&quot;Startups t&amp;#xEA;m cinco mil vagas abertas no pa&amp;#xED;s &amp;#xE0; espera de trabalhadores
Empresas precisam de pessoal qualificado e capaz de entender as mudan&amp;#xE7;as que a tecnologia trouxe para o mundo. Por Jornal Nacional&quot; title=&quot;Startups t&amp;#xEA;m cinco mil vagas abertas no pa&amp;#xED;s &amp;#xE0; espera de trabalhadores
Empresas precisam de pessoal qualificado e capaz de entender as mudan&amp;#xE7;as que a tecnologia trouxe para o mundo. Por Jornal Nacional&quot; src=&quot;/static/cf1d1ae01f92e08c248d5096fc3f2fe8/799d3/9.png&quot; srcset=&quot;/static/cf1d1ae01f92e08c248d5096fc3f2fe8/00d96/9.png 148w,
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    &lt;/span&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;Existia uma época quando a revolução industrial estava a plenos pulmões no Brasil, que era só passar em frente de uma empresa, em geral de metalurgia, que você era praticamente puxado para dentro para trabalhar. &lt;/p&gt;
&lt;p&gt;Os salários eram altos, e os mais velhos diziam que esses sortudos ficavam “bem de vida”, equivalente a ser rico / classe média. Fazer o curso do SENAI, que formava mão de obra geralmente fabril, era praticamente sinônimo de uma carreira de sucesso.&lt;/p&gt;
&lt;p&gt;As mudanças sempre aconteceram, no mundo e nos mercados, mas não com a velocidade que está acontecendo atualmente. Estamos entrando em &lt;strong&gt;uma nova revolução industrial&lt;/strong&gt;, a da &lt;strong&gt;informação&lt;/strong&gt;, e com o advento da globalização, todos os países estão participando desta corrida.&lt;/p&gt;
&lt;p&gt;Os catalisadores desse processo de revolução tecnológica ocorre principalmente através das empresas, que necessariamente precisam de pessoas. As regras e cultura das empresas, antes rígidas, passam a ser mais flexíveis e menos rigorosas, não pelo fato das empresas serem boazinhas, mas pela necessidade de adequação.&lt;/p&gt;
&lt;p&gt;Essa necessidade de manter o bem-estar dos funcionários para não perdê-los para os concorrentes, faz com que as empresas afrouxem as regras, principalmente as de contratação de pessoas. A lei dos mercados é implacável, quando se tem muita demanda e pouca gente, as empresas tornam-se desesperadas.&lt;/p&gt;
&lt;p&gt;Este desespero, abre margem para que as empresas, com sabedoria, selecionem as pessoas por suas habilidades em resolverem problemas, e não por terem o diploma de ensino superior. Isso abre um precedente inédito, que permite que qualquer um consiga construir uma carreira ganhando salários enormes mesmo sem ter concluído uma faculdade.&lt;/p&gt;
&lt;p&gt;Antes que você ache que eu estou vendendo um sonho falso, isso não significa que vai ser fácil, mas muita gente acha que programação é algo impossível de se aprender, e na verdade não é esse bicho de sete cabeças! A gente já fez o trabalho difícil para você, que é o de separar os melhores conteúdos e as melhores dicas para você construir uma carreira sólida como programador, agora só basta a sua força de vontade em vir aprender conosco.&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Isso que vai te garantir um futuro muito confortável e livre do fantasma do desemprego.&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Qualquer um pode ser programador, eu diria que os requisitos básicos são:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;Gostar de computadores e tecnologia&lt;/li&gt;
&lt;li&gt;Ser curioso&lt;/li&gt;
&lt;li&gt;Ter vontade de aprender&lt;/li&gt;
&lt;li&gt;Querer melhorar sempre&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;Em nossa plataforma, eu te ensino tudo que aprendi com 10 anos de experiência de programador com muito suor e conhecimento prático e te tornar um programador apto a trabalhar em &lt;strong&gt;apenas um ano&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Se você quer mudar de vida e transformar a sua carreira HOJE vem com a gente que vamos te ajudar! &lt;a href=&quot;http://http://bit.ly/form-reativa&quot; title=&quot;clique aqui e comece HOJE a se tornar um programador&quot;&gt;clique aqui e comece HOJE a se tornar um programador&lt;/a&gt;.&lt;/p&gt;</content:encoded></item><item><title><![CDATA[Hello World]]></title><description><![CDATA[A Reativa nasceu com o propósito de organizar conteúdos para que você tenha conhecimentos suficientemente profundos para conseguir um…]]></description><link>https://blog.reativa.dev/hello-world/</link><guid isPermaLink="false">https://blog.reativa.dev/hello-world/</guid><pubDate>Wed, 01 Jan 2020 00:00:00 GMT</pubDate><content:encoded>&lt;p&gt;A Reativa nasceu com o propósito de organizar conteúdos para que você tenha conhecimentos suficientemente profundos para conseguir um emprego de programador mesmo não tendo uma faculdade. Em 1 ano de treinamento dedicado você vai ter mais conhecimentos que a maioria dos estudantes que tenham finalizado qualquer graduação voltada para a área de TI.&lt;/p&gt;
&lt;p&gt;Os criadores de conteúdo da Reativa foram os responsáveis por estruturar times de diversas consultorias e startups, sabemos exatamente o que o mercado requer, tanto em termos práticos quanto em soft skills, focaremos no que é extremamente necessário e , ao contrário das faculdades, não faremos você perder um segundo de tempo sequer.&lt;/p&gt;
&lt;p&gt;Por isso nossa proposta é desafiadora:&lt;/p&gt;
&lt;blockquote&gt;
&lt;p&gt;Ensinar em 1 ano o que as faculdades não ensinam em 5&lt;/p&gt;
&lt;/blockquote&gt;
&lt;p&gt;Se você, assim como eu, está disposto a mudar a sua vida através de trabalho duro, dedicação, muito esforço e não acredita em fórmulas mágicas esse conteúdo é pra você.&lt;/p&gt;
&lt;p&gt;Vamos trocar uma idéia? &lt;a href=&quot;https://docs.google.com/forms/d/e/1FAIpQLSdfcrv1T1mBOA9mpryRsBfXq1u_xB3GjmMdVaNrI7nSFvDTfg/viewform&quot;&gt;deixe seu melhor email&lt;/a&gt; e entenda melhor a nossa proposta.&lt;/p&gt;</content:encoded></item></channel></rss>