feat: rewrite the library in typescript for Postal v2

.gitignore

@@ -1,2 +1,3 @@
 node_modules
 .DS_Store
+dist

.prettierrc

@@ -0,0 +1,8 @@
+{
+    "arrowParens": "avoid",
+    "printWidth": 80,
+    "semi": true,
+    "singleQuote": true,
+    "trailingComma": "all",
+    "tabWidth": 4
+}

README.md

@@ -1,69 +1,68 @@
 # Postal for Node
 
 This library helps you send e-mails through the open source mail delivery
-platform, [Postal](https://github.com/atech/postal) in Node.
+platform, [Postal](https://github.com/postalserver/postal) in Node.
 
 ## Installation
 
-Install the library using [NPM](https://www.npmjs.com/):
+Install the library using [NPM](https://www.npmjs.com/) or [Yarn](https://classic.yarnpkg.com/lang/en/docs/install/):
 
 ```
-$ npm install @atech/postal --save
+$ npm install @atech/postal
+$ yarn install @atech/postal
 ```
 
 ## Usage
 
 Sending an email is very simple. Just follow the example below. Before you can
 begin, you'll need to login to your installation's web interface and generate
-new API credentials.
+new API credentials. This package assumes you are on Postal v2.
 
 ```javascript
 // Include the Postal library
-var Postal = require('@atech/postal');
-
-// Create a new Postal client using a server key generated using your
-// installation's web interface
-var client = new Postal.Client('https://postal.yourdomain.com', 'your-api-key');
-
-// Create a new message
-var message = new Postal.SendMessage(client);
-
-// Add some recipients
-message.to('[email protected]');
-message.to('[email protected]');
-message.cc('[email protected]');
-message.bcc('[email protected]');
-
-// Specify who the message should be from - this must be from a verified domain
-// on your mail server
-message.from('[email protected]');
-
-// Set the subject
-message.subject('Hi there!');
-
-// Set the content for the e-mail
-message.plainBody('Hello world!');
-message.htmlBody('<p>Hello world!</p>');
-
-// Add any custom headers
-message.header('X-PHP-Test', 'value');
-
-// Attach any files
-message.attach('textmessage.txt', 'text/plain', 'Hello world!');
-
-// Send the message and get the result
-message.send()
-  .then(function (result) {
-    var recipients = result.recipients();
-    // Loop through each of the recipients to get the message ID
-    for (var email in recipients) {
-      var message = recipients[email];
-      console.log(message.id());    // Logs the message ID
-      console.log(message.token()); // Logs the message's token
-    }
-  }).catch(function (error) {
-    // Do something with the error
-    console.log(error.code);
-    console.log(error.message);
-  });
+const Postal = require('@atech/postal').default; // CommonJS
+// OR
+import Postal from '@atech/postal' // ES6 import
+
+// Create a new Postal client using a server key generated using your installation's web interface
+const client = new Postal({
+    hostname: 'https://postal.yourdomain.com',
+    apiKey: 'your-api-key',
+});
+
+// This must be in an async function
+try {
+    // Send a new message
+    const message = await client.sendMessage({
+        // Set the subject
+        subject: 'Hi there!',
+        // Specify who the message should be from - this must be from a verified domain on your mail server
+        from: '[email protected]',
+        // Add some recipients
+        to: ['[email protected]', '[email protected]'],
+        cc: ['[email protected]'],
+        bcc: ['[email protected]'],
+        // Set the content for the e-mail
+        plain_body: 'Hello world!',
+        html_body: '<p>Hello world!</p>',
+        // Add any custom headers
+        headers: {
+            'X-PHP-Test': 'value',
+        },
+        // Attach any files
+        attachments: [
+            {
+                content_type: 'text/plain',
+                data: Buffer.from('Hello world!').toString('base64'),
+                name: 'textmessage.txt',
+            },
+        ],
+    });
+
+    // Do something with the returned data
+    console.log(message);
+} catch (error) {
+    // Handle the error
+    console.log(error);
+}
 ```