「大坑」關於 module 模式下如何正確引入 WebSocketServer

WebSocket.Server 不是一個構造函數

遇到上述錯誤時，直接按照 cjs 的寫法改成 mjs 形式，但是無法使用；

import WebSocket from "ws"
console.log(typeof WebSocket)
console.log(typeof WebSocket.Server)
// function
// undefined

以報錯的「WebSocket.Server 不是一個構造函數」作為關鍵詞並未找到原因；

直到我換了個方式，直接搜索「import WebSocket from 'ws'」，得到的程式碼如下：

import WebSocket, { WebSocketServer } from 'ws';
console.log(typeof WebSocket)
console.log(typeof WebSocketServer)
// function
// function

然後我去看了 ws 這個庫的導出文件；

// cjs
'use strict';

const WebSocket = require('./lib/websocket');

WebSocket.createWebSocketStream = require('./lib/stream');
WebSocket.Server = require('./lib/websocket-server');
WebSocket.Receiver = require('./lib/receiver');
WebSocket.Sender = require('./lib/sender');

WebSocket.WebSocket = WebSocket;
WebSocket.WebSocketServer = WebSocket.Server;

module.exports = WebSocket;

// mjs
import createWebSocketStream from './lib/stream.js';
import Receiver from './lib/receiver.js';
import Sender from './lib/sender.js';
import WebSocket from './lib/websocket.js';
import WebSocketServer from './lib/websocket-server.js';

export { createWebSocketStream, Receiver, Sender, WebSocket, WebSocketServer };
export default WebSocket;

差異不僅僅是有點大好嗎 Orz；