求助：解决TypeError: mongoose.model is not a function错误

问题概述 #

在Next.js项目中调用mongoose.model()时触发TypeError: mongoose.model is not a function错误，已尝试以下修复操作但未解决：

• 重装mongoose依赖
• 将export default改为module.exports
• 修改MONGO_URI为mongodb://127.0.0.1:27017/
• 在Product.js中改用import导入mongoose
• 移除代码中的mongoose.model = {}
• 在getproducts.js中调整导入顺序，先导入connectDb再导入Product

错误栈信息 #

error - models\Product.js (23:24) @ model
error - TypeError: mongoose.model is not a function
    at eval (webpack-internal:///(api)/./models/Product.js:48:75)
    at (api)/./models/Product.js (C:\Users\CoreCom\Desktop\next js\havenwear\.next\server\pages\api\getproducts.js:42:1)
    at __webpack_require__ (C:\Users\CoreCom\Desktop\next js\havenwear\.next\server\webpack-api-runtime.js:33:42)
    at eval (webpack-internal:///(api)/./src/pages/api/getproducts.js:5:73)
    at (api)/./src/pages/api/getproducts.js (C:\Users\CoreCom\Desktop\next js\havenwear\.next\server\pages\api\getproducts.js:52:1)
    at __webpack_require__ (C:\Users\CoreCom\Desktop\next js\havenwear\.next\server\webpack-api-runtime.js:33:42)
    at __webpack_exec__ (C:\Users\CoreCom\Desktop\next js\havenwear\.next\server\pages\api\getproducts.js:62:39)
    at C:\Users\CoreCom\Desktop\next js\havenwear\.next\server\pages\api\getproducts.js:63:28
    at Object.<anonymous> (C:\Users\CoreCom\Desktop\next js\havenwear\.next\server\pages\api\getproducts.js:66:3)
    at Module._compile (node:internal/modules/cjs/loader:1218:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1272:10)
    at Module.load (node:internal/modules/cjs/loader:1081:32)
    at Module._load (node:internal/modules/cjs/loader:922:12)
    at Module.require (node:internal/modules/cjs/loader:1105:19)
    at require (node:internal/modules/cjs/helpers:103:18)
    at DevServer.runApi (C:\Users\CoreCom\Desktop\next js\havenwear\node_modules\next\dist\server\next-server.js:506:34)
    at DevServer.handleApiRequest (C:\Users\CoreCom\Desktop\next js\havenwear\node_modules\next\dist\server\next-server.js:861:21)
    at Object.fn (C:\Users\CoreCom\Desktop\next js\havenwear\node_modules\next\dist\server\next-server.js:815:46)
    at async Router.execute (C:\Users\CoreCom\Desktop\next js\havenwear\node_modules\next\dist\server\router.js:243:32)
    at async DevServer.runImpl (C:\Users\CoreCom\Desktop\next js\havenwear\node_modules\next\dist\server\base-server.js:432:29)
    at async DevServer.run (C:\Users\CoreCom\Desktop\next js\havenwear\node_modules\next\dist\server\dev\next-dev-server.js:814:20)
    at async DevServer.handleRequestImpl (C:\Users\CoreCom\Desktop\next js\havenwear\node_modules\next\dist\server\base-server.js:375:20)
    at async C:\Users\CoreCom\Desktop\next js\havenwear\node_modules\next\dist\server\base-server.js:157:99
  21 |   // module.exports = mongoose.model("Product", ProductSchema);
  22 |
> 23 | export default mongoose.model("Product", ProductSchema);

相关代码片段 #

Product.js #

const mongoose = require('mongoose');

const ProductSchema = new mongoose.Schema({
    title: {type: String, required:true},
    slug: {type: String, required:true , unique:true},
    desc: {type: String, required:true},
    img: {type: String, required:true},
    category: {type: String, required:true},
    size: {type: String},
    color: {type: String},
    price: {type: Number, required:true},
    availableQty: {type: Number, required:true},
    
    
  }, {timestamps:true} );
  mongoose.model = {}

  // mongoose.model("Product", ProductSchema)
  // module.exports = mongoose.model("Product", ProductSchema);

export default mongoose.model("Product", ProductSchema);

mongoose.js（数据库连接中间件） #

import mongoose from "mongoose";
const connectDb = handler => async (req, res) => {
    // 检查连接是否已建立
    if(mongoose.connections[0].readyState){
        return handler(req,res)
    }
    
    await mongoose.connect(process.env.MONGO_URI)
    return handler(req,res);
}
export default connectDb

getproducts.js（API接口） #

import Product from "../../../models/Product"
import connectDb from "../../../middleware/mongoose"
const handler = async (req,res)=>{
    let products = await Product.find()
    res.status(200).json({products})
  }

export default connectDb(handler)

.env.local（环境变量） #

MONGO_URI=mongodb://localhost:27017/codeswears

核心解决方案 #

问题的根源在于Product.js中mongoose.model = {}这行代码直接覆盖了mongoose内置的model方法，导致后续调用mongoose.model()时找不到对应的函数。即使尝试移除这行代码，可能存在缓存未彻底生效的情况，需按以下步骤操作：

1. 彻底删除mongoose.model = {}：确保Product.js中没有这行代码，这是最关键的修复点。
2. 统一导入方式：避免在同一个项目中混用require和import，将Product.js中的导入改为import mongoose from 'mongoose';，保持和其他文件一致的ES模块语法。
3. 清理缓存并重启项目：删除.next文件夹和node_modules/.cache，然后重新安装依赖并启动项目：

   rm -rf .next node_modules/.cache
   npm install
   npm run dev
   

4. 验证数据库连接逻辑：确保connectDb中间件在模型导入前执行，保证mongoose已完成初始化。调整getproducts.js的导入顺序，先导入connectDb再导入Product：

   import connectDb from "../../../middleware/mongoose"
   import Product from "../../../models/Product"
   

验证修复 #

完成上述操作后，重新调用/api/getproducts接口，若能正常返回产品数据，则问题已解决。如果仍有错误，检查mongoose版本是否与Next.js兼容，建议使用mongoose v6或v7版本（Next.js 13+对v8版本兼容性可能存在问题）。

内容的提问来源于stack exchange，提问作者Afeef Raza