如何用socket.io制作房间系统？

const express = require('express');
const app = express();
const server = require('http').createServer(app);
const io = require('socket.io')(server);

// 服务器监听端口
server.listen(3000, () => {
  console.log('Server is running on port 3000');
});

io.on('connection', (socket) => {
  socket.on('joinRoom', (room) => {
    socket.join(room);
    console.log(`User joined room: ${room}`);
  });
});

io.on('connection', (socket) => {
  socket.on('joinRoom', (room) => {
    socket.join(room);
    console.log(`User joined room: ${room}`);
  });

  socket.on('message', (data) => {
    io.to(data.room).emit('message', data.message);
  });
});

<script src="https://cdn.socket.io/socket.io-3.1.3.min.js"></script>
<script>
  const socket = io('http://localhost:3000');

  // 加入房间
  socket.emit('joinRoom', 'room1');

  // 发送消息
  socket.emit('message', {
    room: 'room1',
    message: 'Hello, room1!'
  });

  // 接收消息
  socket.on('message', (message) => {
    console.log('Received message:', message);
  });
</script>