Getting Started with NestJS: A Comprehensive Introduction

Node.js has become a popular choice due to its efficiency and scalability in the world of backend development. However, building robust and maintainable applications with Node.js often requires structuring your code in a clean and organized manner. This is where NestJS comes into play. NestJS is a progressive Node.js framework that utilises TypeScript to build efficient and reliable server-side applications. In this beginner’s guide, Saigon Digital will explore the basics of NestJS along with some code snippets to help you get started.

What is NestJS?

NestJS is a framework for building server-side applications with Node.js. It is heavily inspired by Angular, leveraging concepts like dependency injection, decorators, and modules to provide a scalable and maintainable architecture. NestJS is built with TypeScript, which adds static typing to JavaScript and helps catch errors during development, making your codebase more robust.

Why Saigon Digital Chose NestJS?

Our partnership with Visa Hotel Now, an innovative leader in the hotel industry, demonstrated our capability to tackle complex challenges and achieve ambitious go-live dates. Visa Hotel Now required a robust and seamless reservation system that allowed clients to register visas and book hotels swiftly. They also needed real-time price updates and several sophisticated features. NestJS proved to be the perfect solution, meeting all their requirements efficiently.

Installation

Before we dive into coding, let’s start by installing NestJS. You can use the following command to create a new NestJS project using the Nest CLI:

npm install -g @nestjs/cli
nest new project-name
cd project-name

This will create a new NestJS project with the necessary boilerplate code.

Creating a Controller

Controllers are responsible for handling incoming requests and returning responses to the client. Let’s create a simple controller that responds with a “Hello World!” message.

// src/app.controller.ts

import { Controller, Get } from '@nestjs/common';

@Controller()
export class AppController {
Ty  @Get()
  getHello(): string {
    return 'Hello, World!';
  }
}

Creating a Module

Use modules to organise the application into cohesive blocks of functionality. Let’s create a module for our controller.

// src/app.module.ts

import { Module } from '@nestjs/common';
import { AppController } from './app.controller';

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

Bootstrapping the Application

Now let’s bootstrap our NestJS application by creating an entry point.

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

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

Running the Application

To run the application, use the following command:

npm run start

Now, if you navigate to http://localhost:3000 in your browser, you should see the “Hello World!” message.

Conclusion

In this beginner’s guide, we’ve covered the basics of NestJS and created a simple application with a controller, module, and entry point. NestJS provides a robust foundation for building scalable and maintainable server-side applications with Node.js. As you continue your journey with NestJS, explore its features like middleware, providers, and advanced decorators to build more complex applications. Happy coding!

• Learn more: Building RESTful APIs with NestJS: A Step-by-Step Guide

Ready to transform your backend development with NestJS? Contact Saigon Digital today to schedule a call with our experts and explore how we can help you build scalable and maintainable server-side applications.