NestJS新建模块报错排查：确认语法无误、换TypeScript版本仍未解决

我是NestJS新手，创建新项目后编写了Users模块，但出现报错。已确认代码语法无误，尝试更换TypeScript版本为4.9，问题仍未解决。

模块代码 #

users/users.module.ts #

import { Module } from '@nestjs/common';
import { UsersController } from './users.controller';
import { UsersService } from './users.service';

@Module({
  imports: [],
  controllers: [UsersController],
  providers: [UsersService],
})
export class UsersModule {}

users/users.service.ts #

import { Injectable } from '@nestjs/common';

@Injectable()
export class UsersService{
  getHello(): string {
    return 'Hello World!';
  }
}

users/users.controller.ts #

import { Controller, Get } from '@nestjs/common';
import { UsersService} from './users.service';

@Controller()
export class UsersController {
  constructor(private readonly appService: UsersService) {}

  @Get()
  getHello(): string {
    return this.appService.getHello();
  }
}

项目依赖配置 #

{
  "name": "server_2",
  "version": "0.0.1",
  "description": "",
  "author": "",
  "private": true,
  "license": "UNLICENSED",
  "scripts": {
    "build": "nest build",
    "format": "prettier --write \"src/**/*.ts\" \"test/**/*.ts\"",
    "start": "nest start",
    "start:dev": "nest start --watch",
    "start:debug": "nest start --debug --watch",
    "start:prod": "node dist/main",
    "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
    "test": "jest",
    "test:watch": "jest --watch",
    "test:cov": "jest --coverage",
    "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
    "test:e2e": "jest --config ./test/jest-e2e.json"
  },
  "dependencies": {
    "@nestjs/common": "^10.0.0",
    "@nestjs/core": "^10.0.0",
    "@nestjs/platform-express": "^10.0.0",
    "reflect-metadata": "^0.1.13",
    "rxjs": "^7.8.1"
  },
  "devDependencies": {
    "@nestjs/cli": "^10.0.0",
    "@nestjs/schematics": "^10.0.0",
    "@nestjs/testing": "^10.0.0",
    "@types/express": "^4.17.17",
    "@types/jest": "^29.5.2",
    "@types/node": "^20.3.1",
    "@types/supertest": "^2.0.12",
    "@typescript-eslint/eslint-plugin": "^6.0.0",
    "@typescript-eslint/parser": "^6.0.0",
    "eslint": "^8.42.0",
    "eslint-config-prettier": "^9.0.0",
    "eslint-plugin-prettier": "^5.0.0",
    "jest": "^29.5.0",
    "prettier": "^3.0.0",
    "source-map-support": "^0.5.21",
    "supertest": "^6.3.3",
    "ts-jest": "^29.1.0",
    "ts-loader": "^9.4.3",
    "ts-node": "^10.9.1",
    "tsconfig-paths": "^4.2.0",
    "typescript": "^5.1.3"
  },
  "jest": {
    "moduleFileExtensions": [
      "js",
      "json",
      "ts"
    ],
    "rootDir": "src",
    "testRegex": ".*\\.spec\\.ts$",
    "transform": {
      "^.+\\.(t|j)s$": "ts-jest"
    },
    "collectCoverageFrom": [
      "**/*.(t|j)s"
    ],
    "coverageDirectory": "../coverage",
    "testEnvironment": "node"
  }
}

报错信息 #

截图显示的错误包括：

• Cannot find name 'Module'.ts(2304)
• Cannot find name 'Injectable'.ts(2304)
• Cannot find name 'Controller'.ts(2304)
• Cannot find name 'Get'.ts(2304)

解决方案 #

1. 检查TypeScript配置 #

NestJS依赖装饰器特性，必须确保tsconfig.json中开启以下选项：
打开项目根目录的tsconfig.json，确认compilerOptions包含：

"experimentalDecorators": true,
"emitDecoratorMetadata": true

完整的推荐配置如下：

{
  "compilerOptions": {
    "module": "commonjs",
    "declaration": true,
    "removeComments": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "allowSyntheticDefaultImports": true,
    "target": "ES2021",
    "sourceMap": true,
    "outDir": "./dist",
    "baseUrl": "./",
    "incremental": true,
    "skipLibCheck": true,
    "strictNullChecks": false,
    "noImplicitAny": false,
    "strictBindCallApply": false,
    "forceConsistentCasingInFileNames": false,
    "noFallthroughCasesInSwitch": false
  }
}

修改后重启开发服务器（npm run start:dev）。

2. 重新安装依赖 #

如果配置没问题，尝试删除依赖文件重新安装：

rm -rf node_modules package-lock.json
npm install

3. 确认模块导入到根模块 #

确保UsersModule已经导入到src/app.module.ts中：

import { Module } from '@nestjs/common';
import { UsersModule } from './users/users.module';

@Module({
  imports: [UsersModule],
})
export class AppModule {}

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