WebSocket in Express Node JS

index.js

const express = require('express');
const http = require('http');
const WebSocket = require('ws');

const app = express();
const server = http.createServer(app);
const wss = new WebSocket.Server({ server });

const PORT = process.env.PORT || 3000;

app.get('/', (req, res) => {
  res.sendFile(__dirname + '/index.html');
});

wss.on('connection', (ws) => {
  console.log('A user connected');

  ws.on('message', (msg) => {
    const message = msg.toString();
    console.log('Message received:', message);
    ws.send('Server received: ' + message);
  });

  ws.on('close', () => {
    console.log('User disconnected');
  });
});

server.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
  console.log(`WebSocket connection address: ws://localhost:${PORT}`);
});