app.js

const http = require('http');

const hostname = '127.0.0.1';
const port = 3000;

http.createServer((req, res) => {
  res.writeHead(200, {
    'Content-Type': 'text/plain'
  });
  res.end('Hello World\n');
}).listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});