Next.js 13.2 App目录下API引入Mongoose连接MongoDB遭遇TypeError错误求助

大家好，我正在用Next.js 13.2的App Router开发项目，尝试连接MongoDB时遇到了一个TypeError，卡了好一阵子，希望能得到大家的帮助。

我的代码文件 #

app/api/hello/route.js（原hello.js）

import connectMongo from '../../../util/connectDB';
import UserModel from '../../../models/UserModel';
import { NextResponse } from 'next/server'

export async function GET(request) {
  return NextResponse.json({hello: 'Hello, Next.js!'})
}

export async function POST(request) {
  const data = await request.json();
  console.log(data);
  return NextResponse.json(data)
}

util/connectDB.js（注：原文件名拼写为connextDB，我修正了拼写）

import mongoose from 'mongoose';

const connectMongo = () => {
  try {
    const conn = mongoose.connect(process.env.MONGODB_URI, {
      useNewUrlParser: true,
      useUnifiedTopology: true,
      useCreateIndex: true,
    });
    console.log(`MongoDB Connected: ${conn.connection.host}`);
  } catch (error) {
    console.error(`Error: ${error.message}`);
    process.exit(1);
  }
};

export default connectMongo;

遇到的错误信息 #

error - node_modules/mongoose/lib/types/objectid.js (21:31) @ prototype
error - TypeError: Cannot read properties of undefined (reading 'prototype')
at eval (webpack-internal:///(sc_server)/./node_modules/mongoose/lib/types/objectid.js:15:36)
at Object.(sc_server)/./node_modules/mongoose/lib/types/objectid.js (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/app/api/hello/route.js:2728:1)
at webpack_require (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/webpack-runtime.js:33:43)
at eval (webpack-internal:///(sc_server)/./node_modules/mongoose/lib/drivers/node-mongodb-native/collection.js:7:18)
at Object.(sc_server)/./node_modules/mongoose/lib/drivers/node-mongodb-native/collection.js (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/app/api/hello/route.js:451:1)
at webpack_require (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/webpack-runtime.js:33:43)
at eval (webpack-internal:///(sc_server)/./node_modules/mongoose/lib/drivers/node-mongodb-native/index.js:4:22)
at Object.(sc_server)/./node_modules/mongoose/lib/drivers/node-mongodb-native/index.js (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/app/api/hello/route.js:473:1)
at webpack_require (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/webpack-runtime.js:33:43)
at eval (webpack-internal:///(sc_server)/./node_modules/mongoose/lib/index.js:4:100)
at Object.(sc_server)/./node_modules/mongoose/lib/index.js (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/app/api/hello/route.js:2057:1)
at webpack_require (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/webpack-runtime.js:33:43)
at eval (webpack-internal:///(sc_server)/./node_modules/mongoose/index.js:5:18)
at Object.(sc_server)/./node_modules/mongoose/index.js (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/app/api/hello/route.js:242:1)
at webpack_require (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/webpack-runtime.js:33:43)
at eval (webpack-internal:///(sc_server)/./models/UserModel.js:5:66)
at Module.(sc_server)/./models/UserModel.js (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/app/api/hello/route.js:154:1)
at webpack_require (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/webpack-runtime.js:33:43)
at eval (webpack-internal:///(sc_server)/./app/api/hello/route.js:6:75)
at Module.(sc_server)/./app/api/hello/route.js (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/app/api/hello/route.js:143:1)
at webpack_require (/Users/avinashsethu/Desktop/Development/ekali-lms/.next/server/webpack-runtime.js:33:43)
at eval (webpack-internal:///(sc_server)/./node_modules/next/dist/build/webpack/loaders/next-app-loader.js?name=app%2Fapi%2Fhello%2Froute&appPaths=&pagePath=private-next-app-dir%2Fapi%2Fhello%2Froute.js&appDir=%2FUsers%2Favinashsethu%2FDesktop%2FDevelopment%2Fekali-lms%2Fapp&pageExtensions=tsx&pageExtensions=ts&pageExtensions=jsx&pageExtensions=js&rootDir=%2FUsers%2Favinashsethu%2FDesktop%2FDevelopment%2Fekali-lms&isDev=true&tsconfigPath=tsconfig.json&assetPrefix=!:13:130)
at Module.(sc_server)/./node_modules/next/dist/build/webpack/loaders/next-app-loader.js?name=app%2Fapi%2Fhello%2Froute&appPaths=&pagePath=private-next-app-dir%2Fapi%2Fhello%2Froute.js&appDir=%2FUsers%2Favinashsethu%2FDesktop%2FDevelopment%2Fekali-lms%2Fapp&pageExtensions=tsx&pageExtensions=ts&pageExtensions=jsx&pageExtensions=js&rootDir=%2FUsers%2Favinashsethu%2FDesktop%2FDevelopment%2Fekali-lms&isDev=true&tsconfigPath=tsconfig.json&assetPrefix=!
at /Users/avinashsethu/Desktop/Development/ekali-lms/node_modules/next/dist/server/load-components.js:49:73
at async Object.loadComponentsImpl [as loadComponents] (/Users/avinashsethu/Desktop/Development/ekali-lms/node_modules/next/dist/server/load-components.js:49:26)
at async DevServer.findPageComponentsImpl (/Users/avinashsethu/Desktop/Development/ekali-lms/node_modules/next/dist/server/next-server.js:599:36) {
page: '/api/hello'
}

我现在必须解决这个MongoDB连接的问题，不然没法继续开发我的应用。我已经检查过环境变量里的MONGODB_URI是正确的，也尝试过重启开发服务器，但还是报这个错。有没有大佬能帮忙分析下问题出在哪，或者给些可行的解决方案？

补充：可能的排查方向（供参考） #

• 版本兼容性问题：Next.js 13 App Router对Mongoose版本有要求，旧版本（比如6.x）可能和Next.js的服务器组件打包逻辑不兼容，建议升级到Mongoose 7.x以上：

  npm install mongoose@latest
  

• 连接函数的异步问题：原connectMongo函数里，mongoose.connect是异步操作，但没有用await，导致conn是Promise对象而非实际连接实例，conn.connection.host会报错。可以改成异步函数并添加单例判断避免重复连接：

  import mongoose from 'mongoose';
  
  let isConnected = false;
  
  const connectMongo = async () => {
    if (isConnected) {
      console.log('已连接MongoDB，无需重复连接');
      return;
    }
    try {
      const conn = await mongoose.connect(process.env.MONGODB_URI);
      isConnected = true;
      console.log(`MongoDB Connected: ${conn.connection.host}`);
    } catch (error) {
      console.error(`连接失败：${error.message}`);
      process.exit(1);
    }
  };
  
  export default connectMongo;
  

• UserModel的定义问题：错误追踪到了UserModel的第5行，可能模型里使用了Mongoose已废弃的API，或者重复创建模型。建议模型定义时添加判断避免热重载重复注册：

  // models/UserModel.js示例
  import mongoose from 'mongoose';
  
  const userSchema = new mongoose.Schema({
    name: String,
    email: { type: String, unique: true },
  });
  
  export default mongoose.models.User || mongoose.model('User', userSchema);
  

备注：内容来源于stack exchange，提问作者Avinash Sethu