问Socket.IO-客户机在React.js中不连接

EN

import React, { useState, useEffect } from 'react';
import queryString from 'query-string';
import io from 'socket.io-client';

let socket;

const Chat = ({ location }) => {
    const [name, setName] = useState('');
    const [room, setRoom] = useState('');
    const ENDPOINT = 'http://localhost:5000';
    useEffect(() => {
        const { name, room } = queryString.parse(location.search);
        socket = io(ENDPOINT);

        setName(name);
        setRoom(room);

        console.log(socket);
    });
    return (
        <>
            <h2>Chat</h2>
            <h3>Check </h3>
        </>
    );
}
export default Chat;

const express = require('express');
const socketio = require('socket.io');
const http = require('http');

const PORT = process.env.PORT || 5000;
const router = require('./router');

const app = express();
const server = http.createServer(app);
const io = socketio(server);

io.on('connect', (socket) => {
    console.log('we have a new connection!!!');

    socket.on('disconnect', () => {
        console.log('User had left!!');
    });
});
app.use(router);
server.listen(PORT, () => console.log(`Server has started on port ${PORT}`));