TypeScript创建Mongoose模型静态方法时报找不到mongoose命名空间如何解决

• 导入mongoose的方式为CommonJS的require语法，TypeScript无法正确识别加载的模块类型，导致无法读取mongoose命名空间下的类型定义
• Mongoose v5及更早版本未内置TypeScript类型声明，若未安装对应的类型依赖包也会触发该报错
• 继承mongoose.Model时未传入对应文档类型的泛型参数，类型校验不通过
• 调用mongoose.model时未指定自定义模型的泛型，TypeScript无法识别新增的静态方法类型

1. 替换导入语法
   将const mongoose = require('mongoose')替换为ES模块导入语法：

import mongoose from 'mongoose'

如果你的tsconfig.json中未开启esModuleInterop配置，可使用：

import * as mongoose from 'mongoose'

2. 安装类型依赖（仅Mongoose v5及更早版本需要）
   Mongoose v6+已内置完整TypeScript类型定义，无需额外安装。低版本用户执行以下命令安装类型依赖：

npm install @types/mongoose --save-dev

3. 修正接口类型定义
   将接口中大写的String改为TS基础类型string，同时为mongoose.Model传入文档属性泛型：

interface UserAttribs {
  email: string;
  password: string;
}

// 传入文档属性泛型，同时声明自定义静态方法
interface UserModel extends mongoose.Model<UserAttribs> {
  build(attribs: UserAttribs): User;
}

4. 调用model方法时指定泛型
   将mongoose.model的返回值指定为你自定义的UserModel类型，让TS识别新增的静态方法：

const User = mongoose.model<UserAttribs, UserModel>('User', userSchema);

完整修正后代码 #

import mongoose from 'mongoose';

interface UserAttribs{
  email: string;
  password: string;
}

interface UserModel extends mongoose.Model<UserAttribs>{
  build(attribs: UserAttribs): User;
}

const userSchema = new mongoose.Schema({
  email:{
    type: String,
    required: true
  },    
  password:{
    type: String,
    required: true
  }    
});

userSchema.statics.build = (attribs: UserAttribs) => {
  return new User(attribs);
}

const User = mongoose.model<UserAttribs, UserModel>('User', userSchema);

export { User };

内容的提问来源于stack exchange，提问作者Pinakin Chaubal