socketio 使用問題

客戶端代碼:

<script>
    var socket = io.connect('http://127.0.0.1:3000/');
    socket.emit('online', {
        user: 'hello'
    });
    socket.on('connect', function() {
        console.log(123123);
    })
    socket.on('error', function(error){
        console.log(error);
    })
</script>

服務(wù)端代碼:

const server = http.createServer(app.callback());

const io = new socketIo(server);

io.on('connection', (socket) => {
    console.log('a user connected')

    socket.on('online', (data) => {
        console.log(data);
    });

    socket.on('disconnect', () => {
        console.log('close connect');
    });
});

部署: 使用PM2 啟動多進(jìn)程以后, 訪問客戶端, 出現(xiàn)

錯誤