Vanilla Node server demonstrating the Node event loop

server.js

const http = require("http");
const { log } = console;

// This just lets us block the event loop
const workFor = 5 // seconds
const work = (s = workFor) => new Promise(r => setTimeout(r, s * 1000));

const appPort = 8888

let reqCount = 0
const server = http.createServer(async (req, res) => {
  if (req.method === "GET") {
    const reqId = ++reqCount;
    log(`REQ:${reqId} : ~working : for ${workFor} seconds`);

    // Simulate doing something - `await` will block here
    await work()
    
    log(`REQ:${reqId} : *done`);
    res.end(`<h1>Done REQ:${reqId}</h1>`);
  }
  res.end()
});

server.listen(appPort, () => log(`App listening on port ${appPort}`));