Socket.io服务器启动失败：TypeError: Server不是构造函数

我正尝试结合Express.js运行Socket.io，以下是我的server.js代码：

const express = require("express");
const app = express();
const http = require("http");
const cors = require("cors");
const Server = require("socket.io");

app.use(cors());
const server = http.createServer(app);

const io = new Server(server, {
  cors: {
    origin: "http://localhost:3000",
    methods: ["GET", "POST"],
  },
});

io.on("connection", (socket) => {
  console.log(`User connected: ${socket.id}`);
  socket.on("Disconnect", () => {
    console.log(`User disconnected: ${socket.id}`);
  });
});

server.listen(3000, () => {
  console.log("SERVER WALKING");
});

运行nodemon server.js后出现如下报错：

const io = new Server(server, {
           ^

TypeError: Server is not a constructor
    at Object.<anonymous> (Path:10:12)
    at Module._compile (node:internal/modules/cjs/loader:1105:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Module._load (node:internal/modules/cjs/loader:827:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:77:12)
    at node:internal/main/run_main_module:17:47

Node.js v18.0.0
[nodemon] app crashed - waiting for file changes before starting...

我已经尝试用npm和yarn删除并重新安装node_modules，但报错仍未解决，请问哪里操作有误？

• 核心问题是Socket.io的导入方式错误：Socket.io v3及以上版本的CommonJS模块中，Server是命名导出，不是默认导出。你当前的写法const Server = require("socket.io");拿到的是整个模块对象，不是构造函数，所以会报错Server is not a constructor。需要改成命名导入：

  const { Server } = require("socket.io");
  

  或者：

  const Server = require("socket.io").Server;
  

• 另外还有一个隐性问题：Socket.io的断开连接事件名是小写的disconnect，你代码里写的是大写的Disconnect，这个事件不会被触发，需要修正。

修正后的完整代码：

const express = require("express");
const app = express();
const http = require("http");
const cors = require("cors");
const { Server } = require("socket.io");

app.use(cors());
const server = http.createServer(app);

const io = new Server(server, {
  cors: {
    origin: "http://localhost:3000",
    methods: ["GET", "POST"],
  },
});

io.on("connection", (socket) => {
  console.log(`User connected: ${socket.id}`);
  socket.on("disconnect", () => {
    console.log(`User disconnected: ${socket.id}`);
  });
});

server.listen(3000, () => {
  console.log("SERVER RUNNING");
});

内容的提问来源于stack exchange，提问作者Talha