导入Mongoose后Node.js服务器崩溃，报语法错误

导入Mongoose后，Node.js服务器立即崩溃，抛出如下语法错误：

/home/kashif/git/edemy/server/node_modules/mongodb/lib/collection.js:74
            pkFactory: db.options?.pkFactory ?? utils_1.DEFAULT_PK_FACTORY,
                                  ^

SyntaxError: Invalid or unexpected token
    at Module._extensions..js (node:internal/modules/cjs/loader:1309:10)

Node.js v20.2.0

未导入Mongoose时服务器运行正常，尝试用Mongoose连接MongoDB数据库，但导入后就触发该错误。相关文件内容如下：

server.js 文件 #

// setting server using express now
import express from "express";
import cors from "cors";

// import fs from "fs"; we dont need the whole file syst instead we can destructure just the readdirSync function

import { readdirSync } from "fs";
import morgan from "morgan";
import mongoose from "mongoose";

// import doenv config

import dotenv from "dotenv";
dotenv.config();

// create express app

const app = express(); // when we execute exrpess that entire express app is available in this variable app

// apply middlewares ( code which runs between request and response)

app.use(cors()); // cors is a middleware which allows to connect to the server from different domain
app.use(express.json()); // express.json() is a middleware which allows to read json data from request body
app.use(morgan("dev")); // morgan is a middleware which logs the request details in the console

//Routes

readdirSync("./routes").map((r) => {
  //apply as middelware now
  app.use("/api", require(`./routes/${r}`));
});

const port = process.env.PORT || 8000; // process.env.PORT is used to get the port number from the .env file and if it is not available then it will use 8000 as default port. Process is a global variable in nodejs which allow us to access the environment variables and other process related information

// start listening to port

app.listen(port, () => {
  console.log(`server is running on port ${port}`);
});

package.json 文件 #

{
  "name": "server",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "nodemon -r esm server.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "bcrypt": "^5.1.1",
    "cors": "^2.8.5",
    "dotenv": "^16.3.1",
    "esm": "^3.2.25",
    "express": "^4.18.2",
    "jsonwebtoken": "^9.0.1",
    "mongoose": "^7.5.0",
    "morgan": "^1.10.0",
    "nodemon": "^3.0.1"
  }
}

1. 替换第三方esm模块加载器为Node.js原生ESM支持 #

错误根源是第三方esm包与MongoDB依赖中的现代JavaScript语法（可选链?.、空值合并??）不兼容。Node.js v12+已原生支持ESM，无需依赖第三方包：

• 卸载esm包：

  npm uninstall esm
  

• 修改package.json，添加"type": "module"并更新启动脚本：

  {
    "name": "server",
    "version": "1.0.0",
    "type": "module", // 新增该行，启用原生ESM
    "description": "",
    "main": "index.js",
    "scripts": {
      "start": "nodemon server.js" // 移除-r esm参数
    },
    // 其余依赖项保持不变
  }
  

• 修复路由导入逻辑（原生ESM不支持require，需改用异步import）：
  修改server.js中的路由代码：

  import { fileURLToPath } from 'url';
  import { dirname, join } from 'path';
  
  const __filename = fileURLToPath(import.meta.url);
  const __dirname = dirname(__filename);
  
  // 封装异步启动逻辑
  const startServer = async () => {
    // 遍历路由文件并导入
    for (const r of readdirSync(join(__dirname, './routes'))) {
      const routerModule = await import(`./routes/${r}`);
      app.use("/api", routerModule.default);
    }
  
    // 启动服务器
    app.listen(port, () => {
      console.log(`server is running on port ${port}`);
    });
  };
  
  startServer();
  

2. 清理依赖缓存并重新安装 #

若仍有问题，清理缓存后重新安装依赖：

rm -rf node_modules package-lock.json
npm install

3. 验证版本兼容性 #

Mongoose 7.x要求Node.js版本≥14.20.0/16.13.0/18.0.0/20.0.0，你的Node.js v20.2.0符合要求。如果问题持续，可尝试升级Mongoose到最新兼容版本：

npm install mongoose@latest

内容的提问来源于stack exchange，提问作者Kashif