⚙️ Backend
🛠️ Backend Frameworks
NestJS

NestJS

NestJS is a progressive Node.js framework for building efficient, reliable, and scalable server-side applications. It leverages TypeScript and combines elements of OOP (Object Oriented Programming), FP (Functional Programming), and FRP (Functional Reactive Programming).

Key Features

TypeScript-First Development

  • Built with and fully supports TypeScript
  • Enhanced IDE support
  • Strict typing and better error catching
  • Improved code maintainability

Architectural Pattern

  • Based on Angular's architecture
  • Modular structure
  • Dependency injection
  • Decorators for enhanced metadata

Built-in Support

  • REST APIs: Complete REST framework
  • GraphQL: First-class GraphQL support
  • WebSockets: Real-time communication
  • Microservices: Built-in microservices patterns

Core Concepts

Modules

@Module({
  imports: [DatabaseModule],
  controllers: [UserController],
  providers: [UserService],
})
export class UserModule {}

Controllers

@Controller('users')
export class UserController {
  @Get()
  findAll(): Promise<User[]> {
    return this.userService.findAll();
  }
}

Providers (Services)

@Injectable()
export class UserService {
  constructor(@InjectRepository(User)
  private usersRepository: Repository<User>) {}
 
  findAll(): Promise<User[]> {
    return this.usersRepository.find();
  }
}

Best Practices

  1. Project Structure

    • Follow modular architecture
    • Separate concerns properly
    • Use feature modules

  2. Exception Handling

    • Implement global exception filters
    • Use built-in HTTP exceptions
    • Create custom exceptions when needed

  3. Validation

    • Use DTOs (Data Transfer Objects)
    • Implement class-validator decorators
    • Add request payload validation

  4. Testing

    • Write unit tests for services
    • Create e2e tests for APIs
    • Use Jest for testing

Getting Started

# Installation
$ npm i -g @nestjs/cli
$ nest new project-name
 
# Running the app
$ npm run start
 
# Development with hot reload
$ npm run start:dev

Common Use Cases

  • REST API development
  • Microservices architecture
  • Real-time applications
  • Enterprise-level applications
  • GraphQL APIs

Additional Resources

Express.jsHono