solution-node-intro.js

// 1: npm i dotenv

// 2: require packages
const http = require('http');
require('dotenv').config();

const PORT = process.env.PORT || 3000; // You can set default port to 3000 if port is not defined

// 3: create server (and use packages):

const myServer = http.createServer((request, response) => {
  console.log(`Success, I'm listening from the port: ${PORT}`);
  response.end();
});

// 4: server listens on the port 3000
myServer.listen(process.env.PORT, () => console.log('I am 🏃‍♂️ on port 3000!'));