Should You Use NestJS to Build Backend APIs?

NestJS is a modern, feature-rich framework for building scalable server-side applications, especially for APIs in Node.js environments.

Introduction

If you’re on the hunt for a framework to build robust and efficient backend APIs, you may have come across NestJS. This TypeScript-based framework is designed to give developers the tools they need to create scalable, maintainable, and easy-to-test server-side applications. In this article, we’ll explore the capabilities of NestJS, compare it with alternative solutions, and see how it can be utilized for building enterprise-level APIs.

Getting Started with NestJS

To kick off your project with NestJS, you need to install Node.js and npm (node package manager) on your computer. Then, install the NestJS CLI (Command Line Interface) using npm:

npm i -g @nestjs/cli

Create a new NestJS project:

nest new project-name

Once the installation process is done, you can run your project using:

cd project-name
npm run start

Your NestJS server will start, and you can open your browser to http://localhost:3000/ to see your new application in action.

Building a Basic API

Let’s set up a simple API to manage a list of tasks. To begin, we need to create a new module, controller, and service for our tasks feature inside the NestJS application:

nest generate module tasks
nest generate controller tasks
nest generate service tasks

In the Tasks module, create a simple DTO (Data Transfer Object) to define the structure of a task:

export class CreateTaskDto {
  title: string;
  description?: string;
}

Now, let’s write a Task Service, in which we will handle our business logic:

import { Injectable } from '@nestjs/common';
import { CreateTaskDto } from './create-task.dto';

@Injectable()
export class TasksService {
  private tasks = [];

  create(task: CreateTaskDto) {
    this.tasks.push(task);
    return task;
  }

  findAll() {
    return this.tasks;
  }
}

Within our Tasks Controller, we can define endpoints to interact with our services:

import { Controller, Get, Post, Body } from '@nestjs/common';
import { TasksService } from './tasks.service';
import { CreateTaskDto } from './create-task.dto';

@Controller('tasks')
export class TasksController {
  constructor(private tasksService: TasksService) {}

  @Post()
  create(@Body() createTaskDto: CreateTaskDto) {
    return this.tasksService.create(createTaskDto);
  }

  @Get()
  findAll() {
    return this.tasksService.findAll();
  }
}

By running the server and using an API testing tool like Postman, you can send GET and POST requests to http://localhost:3000/tasks to see your API in action.

Advanced Features of NestJS

NestJS offers advanced features like dependency injection, modules, middleware, exception filters, pipes, guards, and interceptors, which all work together to provide a rich set of tools for building complex applications. For example, here’s how you could set up a global validation pipe:

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import { ValidationPipe } from '@nestjs/common';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.useGlobalPipes(new ValidationPipe());
  await app.listen(3000);
}
bootstrap();

Integration with ORM frameworks like TypeORM or Sequelize is seamless in NestJS, facilitating easy data manipulation and complex queries to databases. Implementing authentication and authorization is streamlined with built-in strategies, which you can further customize to fit your security needs.

Conclusion

In conclusion, NestJS is a strong candidate for building backend APIs, thanks to its comprehensive toolkit, strong community support, and powerful TypeScript integration. As we delved into the basics and some advanced features of NestJS, we’ve seen that it is not only efficient and scalable, but also enhances productivity and long-term maintainability of server-side applications. By embracing the fundamentals we’ve discussed and leveraging more advanced features, you can position yourself and your projects to take full advantage of what NestJS has to offer.