Beginner's Guide to Building Scalable Node.js Apps with Nest.js

Nest.js is a popular open-source Node.js framework for building scalable and efficient server-side applications. It is built on top of Express.js and provides a modular and flexible architecture that supports a wide range of use cases, from microservices to monolithic applications.

Nest.js leverages TypeScript, a statically typed language that adds features such as classes, interfaces, and decorators to JavaScript, to enhance the development experience and improve code quality. It also supports various other technologies and libraries, such as GraphQL, WebSockets, and MongoDB, making it a versatile and powerful tool for web development.

Getting started with Nest.js is relatively easy. Here are the steps to follow:

Install Node.js and npm

Before getting started with Nest.js, you'll need to have Node.js and npm installed on your system. You can download them from the official website and follow the installation instructions.

Install Nest.js

Once you have Node.js and npm installed, you can install Nest.js using the following command:

javascript
npm install -g @nestjs/cli

This will install the Nest.js CLI globally on your system, which you can use to create new Nest.js projects and generate boilerplate code.

Creating a new Nest.js project

To create a new Nest.js project, navigate to the directory where you want to create the project and run the following command:

Text
nest new my-project

This will create a new Nest.js project named my-project in the current directory and install all the necessary dependencies.

Generate a new controller

Controllers are responsible for handling incoming HTTP requests and returning responses. To generate a new controller, run the following command:

Text
nest generate controller cats

This will create a new CatsController class in the src/cats directory and add it to the app.module.ts file.

Add a route to the controller

Once you have a controller, you can add a route to it by using the @Get decorator. Open the cats.controller.ts file and add the following code:

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

@Controller('cats')
export class CatsController {
  @Get()
  findAll(): string {
    return 'This action returns all cats';
  }
}

This code creates a new route for the /cats URL that returns a simple string response.

Starting the server

To start the Nest.js server, run the following command:

Text
npm run start

This will start the server and make it available on http://localhost:3000.

Here is an example of a complete app.module.ts file for a simple Nest.js application that uses the CatsController we just created:

typescript
import { Module } from '@nestjs/common';
import { CatsController } from './cats/cats.controller';

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

In summary, Nest.js is a powerful Node.js framework that provides a modular and flexible architecture for building scalable and efficient server-side applications. Getting started with Nest.js is relatively easy, and you can create a new project and generate boilerplate code using the Nest.js CLI. With a little bit of code, you can create a fully functional API that can handle incoming requests and return responses.