Introducing NestJS – Modern Backend Framework for Node.js

🔧 1. What is NestJS?

NestJS is an open source framework, combining the power of Express (or Fastify) with Modular and Dependency Injection architectural models similar to Angular.
This makes your code easy to organize and easy to expand when the project becomes complex.

👉 In short:

NestJS = Node.js + TypeScript + Module Architecture + Dependency Injection.

new application with the command:

npm i -g @nestjs/cli
nest new my-project

You will receive a folder structure as follows:

src/
 ┣ app.controller.ts
 ┣ app.controller.spec.ts
 ┣ app.module.ts
 ┣ app.service.ts
 ┗ main.ts

📂 Quick explanation:

• app.module.ts → Root module, where submodules, controllers, provider.

• app.controller.ts → Handles HTTP requests.

• app.service.ts → Contains business logic.

• main.ts → Application startup file.

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⚙️ 3. Create a Simple REST API with NestJS

Suppose you want to create an endpoint /users to return a list of users:

Step 1: Create a new module

nest g module users

Step 2: Create a controller and service

nest g controller users
nest g service users

Step 3: Add logic service

// users.service.ts
import { Injectable } from '@nestjs/common';

@Injectable()
export class UsersService {
  private users = [
    { id: 1, name: 'An Nguyen' },
    { id: 2, name: 'Tuan Le' },
  ];

  findAll() {
    return this.users;
  }
}

Step 4: Use service in controller

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

@Controller('users')
export class UsersController {
  constructor(private readonly usersService: UsersService) {}

  @Get()
  getAllUsers() {
    return this.usersService.findAll();
  }
}

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🧩 4. Advantages of NestJS

✅ Complete TypeScript support.
✅ modularized structure makes it easy to extend.
✅ Integration middleware, guards, interceptors, pipes just like Angular.
✅ Supports GraphQL, WebSocket, Microservices.
✅ Easy testing thanks to dependency injection.

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🧠 5. When should you use NestJS?

NestJS is suitable for:

• Backend projects Need large scale and have many modules.

• Need REST API or GraphQL API.

• Need clear, easy to maintain code.

• Working in large teams need unified standards.

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🔮 6. Conclusion essay

NestJS brings a modern and powerful approach to backend development with Node.js.
If you come from the Angular or Java/Spring Boot world, you will find NestJS very familiar and easy to learn.

💡 Try starting by creating a small REST API with NestJS — you will see that your code is clean and easy to learn. “cleaner” than ever!