main.js

const http = require('http');
const path = require('path');
const fs = require('fs');
const Mustache = require('mustache');
const { isEmpty } = require('lodash');
const { dbClient } = require('./yourNoSql');
const { serveStatic } = require('./serveStatic');

const PORT = process.env.PORT || 9090;

const templateList = {
  userList: {
    content: null,
    fileName: path.join(__dirname, 'templates/userList.html'),
  },
  user: {
    content: null,
    fileName: path.join(__dirname, 'templates/user.html'),
  },
};

/**
 * @param {http.IncomingMessage} req
 * @param {http.ServerResponse} res
 */
async function listener(req, res) {
  if (req.method !== 'GET') {
    res.statusCode = 405;
    res.end();
    return;
  }

  if (req.url === '/' || req.url === '/users' || req.url === '/users/') {
    res.writeHead(302, {
      Location: '/users.html',
    });
    res.end();
    return;
  }

  if (req.url === '/users.html') {
    const users = await dbClient.getList();

    // pending
    // resolved
    // rejected

    res.statusCode = 200;
    const content = Mustache.render(templateList.userList.content, { title: 'User List from data', users });
    res.write(content);
    res.end();

    return;
  }

  if (req.url.startsWith('/users/')) {
    const baseURL = `http://${req.headers.host}/`;
    const myURL = new URL(req.url, baseURL);
    const [,, id] = myURL.pathname.split('/');

    const userUpdateData = Object.fromEntries(myURL.searchParams.entries());

    if (isEmpty(myURL.search)) {
      const user = await dbClient.findUser(id);
      const content = Mustache.render(templateList.user.content, user);
      res.write(content);
      res.end();
      return;
    }

    await dbClient.update(id, userUpdateData);
    res.writeHead(302, {
      Location: '/users.html',
    });
    res.end();
    return;
  }

  serveStatic(req, res);
}

const server = http.createServer(listener);

function listenIfReady() {
  const allLoaded = Object.values(templateList).every((template) => template.content);
  if (allLoaded) {
    server.listen(PORT);
  }
}

Object.entries(templateList).forEach(([templateName, template]) => {
  fs.readFile(template.fileName, 'utf-8', (err, userListContent) => {
    templateList[templateName].content = userListContent;
    listenIfReady();
  });
});