generatePostJson.js

const fs = require("fs");
const glob = require("glob");
const yaml = require("yaml");
const markdownIt = require("markdown-it");

// helper functions

const clearHTMLTags = function (str) {
	return str.replace(/(<([^>]+)>)/gi, "");
};

const clearCommonMDTags = function (str) {
	return str
		.replaceAll("-", "")
		.replaceAll("\n", "")
		.replaceAll("**", "")
		.replaceAll("##", "")
		.replaceAll("\n", "");
};

const getDescriptionFromBody = function (mdFile) {
	const buffer = fs.readFileSync(mdFile);
	let fileContent = buffer.toString();

	// clear meta data
	const metas = /---(.*?)---/s.exec(fileContent);
	if (metas.length > 0) {
		fileContent = fileContent.replaceAll(metas[0], "");
	}

	//try to get first n character as plain text
	let body = "";

	try {
		let md = new markdownIt({
			html: true,
			linkify: true,
			typographer: true,
		});

		body = md.render(fileContent);
		body = clearHTMLTags(body);
		body = clearCommonMDTags(body);
		body = body.slice(0, 160) + "...";
	} catch (e) {}

	return body;
};

const getMetaData = function (mdFile) {
	const buffer = fs.readFileSync(mdFile);
	const fileContent = buffer.toString();
	let metadata = {};

	const metas = /---(.*?)---/s.exec(fileContent);
	if (metas.length > 0) {
		const clearMeta = metas[0].replaceAll("---", "");
		try {
			metadata = yaml.parse(clearMeta);
		} catch ($e) {}
	}

	return metadata;
};

const parseDateFromFileName = function (file) {
	const monthNames = [
		"January",
		"February",
		"March",
		"April",
		"May",
		"June",
		"July",
		"August",
		"September",
		"October",
		"November",
		"December",
	];
	const splited = file.split("-");
	let dateText = "";

	if (splited.length > 3) {
		const year = splited[0] || null;
		const month = splited[1] || null;
		const day = splited[2] || null;

		const date = new Date(`${year}-${month}-${day}`);

		if (Object.prototype.toString.call(date) === "[object Date]") {
			// it is a date
			if (isNaN(date)) {
				// d.getTime() or d.valueOf() will also work
				// date object is not valid
				dateText = "";
			} else {
				dateText = `${monthNames[date.getMonth()]} ${String(
					date.getDate()
				).padStart(2, "0")}, ${date.getFullYear()}`;
			}
		} else {
			dateText = "";
		}
	}

	return dateText;
};

// main process

const langs = ["en", "cn"];

for (const lang of langs) {
	const folder = `./src/contents/posts/${lang}`;

	const postsJson = [];

	fs.readdirSync(folder)
		.reverse()
		.forEach((file) => {
			const mdFiles = glob.globSync(`${folder}/${file}/*.md`);
			if (mdFiles.length > 0) {
				const mdFile = mdFiles[0];

				const metadata = getMetaData(mdFile);

				const imgFiles = glob.globSync(`${folder}/${file}/*.{jpeg,jpg,png}`);

				if (imgFiles.length > 0) {
					let featuredImgPath = imgFiles[0];
					const folderRelative = `${folder}/${file}/`.replace("./", "");
					const featuredImageName = featuredImgPath.replace(folderRelative, "");
					fs.copyFile(
						featuredImgPath,
						`public/img/posts/featuredImg/${featuredImageName}`,
						(err) => {}
					);
				}

				postsJson.push({
					title: metadata.title || "",
					description: metadata.description || getDescriptionFromBody(mdFile),
					author: metadata.author || "",
					tags: metadata.tags || [],
					alias: file,
					date: parseDateFromFileName(file),
					image: metadata.featuredImage,
				});
			}
		});

	fs.writeFileSync(
		`./src/contents/posts.home.${lang}.json`,
		JSON.stringify(postsJson.slice(0, 6), null, 2)
	);

	fs.writeFileSync(
		`./src/contents/posts.${lang}.json`,
		JSON.stringify(postsJson, null, 2)
	);
}