text: const app = require('express')();
  const http = require('http').createServer(app);
  const io = require('socket.io')(http);
  app.get('/', (req, res) => {
      res.sendFile(__dirname + '/index.html');
  });
  io.on('connection', (socket) => {
      console.log('a user connected');
      socket.on('chat message', (msg) => {
          io.emit('chat message', msg);
      });
      socket.on('disconnect', () => {
          console.log('user disconnected');
      });
  });
  http.listen(3000, () => {
      console.log('Connected at 3000');
  });
  