实现简略的websocket，只须要几步：

  1. 引入socket.io组件;
  2. 前端初始化页面时，监听socket.on('chatMsg', () => xxx);
  3. 须要发送事件时，触发socket.emit('chatMsg', 'msg');
  4. 后端监听事件并回调即可
index.html
<!DOCTYPE html><html lang="en"><head>    <meta charset="UTF-8">    <meta name="viewport" content="width=device-width, initial-scale=1.0">    <title>Document</title></head><body>    <div id="app">        <input type="text" id="name">        <button type="button"  @click="submit">send</button>        <ul v-for="(item, i) in msgList" :key="item + new Date().getTime()">            <li>{{i+1}}.{{item}}</li>        </ul>    </div>    <script src="https://cdn.bootcdn.net/ajax/libs/axios/0.21.0/axios.js"></script>    <script src="https://lib.baomitu.com/vue/2.6.12/vue.js"></script>    <script src="https://lib.baomitu.com/socket.io/3.0.1/socket.io.js"></script>    <script>        // 生成对象        let socket = io();        let vm = new Vue({            el: '#app',            data: {                msgList: [],            },            created () {                // 监听                socket.on('chatMsg', (msg) => {                    vm.msgList.push(msg)                })            },            methods: {                submit: async () => {                    let msg = document.getElementById('name').value;                    document.getElementById('name').value = '';                    // 发送事件                    socket.emit('chatMsg', msg);                },            }        })    </script></body></html>
index.js
const express = require('express');const app = express();const http = require('http').Server(app);const io = require('socket.io')(http);app.get('/', (req, res) => {    res.sendFile(__dirname + '/index.html');})// 监听io.on('connection', (socket) => {    console.log('a socket connection....');        // 事件达到时    socket.on('chatMsg', (msg) => {        io.emit('chatMsg', msg);    })        // 链接断开时    socket.on('disconnect', () => {        console.log('disconnect');    })})http.listen(3000, () => {    console.log('http listen 3000............');})