Getting Started With NestJs: A Beginner’s Guide

NestJs is a powerful framework for building scalable, server-side applications. It is built on top of Node.js and is inspired by Angular, which makes it an excellent choice for developers who are already familiar with Angular.

In this beginner’s guide, we will take a closer look at NestJs and provide an overview of its key features, including its architecture, modules, and controllers. We will also walk through the process of setting up a basic NestJs application and creating a simple API endpoint.

What is NestJs?

NestJs is a server-side framework for building scalable, enterprise-grade applications. It is built on top of Node.js and is designed to provide a robust set of features for building complex, server-side applications. NestJs is inspired by Angular, which makes it an excellent choice for developers who are already familiar with Angular.

NestJs Architecture

NestJs uses a modular architecture that is designed to make it easy to build complex, scalable applications. At its core, NestJs is built using a set of modules, which are collections of related components that can be easily plugged into your application. Each module is responsible for a specific set of tasks, such as handling HTTP requests or connecting to a database.

NestJs Modules

Modules are the building blocks of a NestJs application. They are designed to be self-contained and can be easily plugged into your application. Each module can contain components, controllers, providers, and other related files.

In the example above, we have defined a basic module for our NestJs application. The module contains an AppController and an AppService, which we will define next.

NestJs Controllers

Controllers are responsible for handling incoming HTTP requests and returning responses to the client. Controllers are defined within modules and are responsible for specific routes or groups of routes.

In the example above, we have defined a basic AppController. The controller handles incoming HTTP requests to the root route (/) and returns a simple string response.

NestJs Providers

Providers are a key component of a NestJs application. They are used to inject dependencies into components, such as controllers or services. Providers can be defined within modules and can be easily injected into other components.

In the example above, we have defined a basic AppService. The service contains a single method (getHello()) that returns a simple string response.

Getting Started with NestJs

To get started with NestJs, we first need to install the NestJs CLI:

Once we have installed the CLI, we can create a new NestJs application using the nest new command:

This will create a new NestJs application in a directory named my-app. Once the application has been created, we can start the development server using the npm run start:dev command:

This will start the development server, and we can now access our application at http://localhost:3000.

Creating a Simple API Endpoint

Now that we have our NestJs application set up, let’s create a simple API endpoint that returns a list of users. To do this, we will first create a new module:

In the example above, we have defined a new UsersModule that includes a UsersController and a UsersService.

Next, let’s define our UsersController:

In the example above, we have defined a simple UsersController that handles incoming HTTP requests to the /users route.

Let’s define our UsersService:

In the example above, we have defined a simple UsersService that returns a list of users.

Finally, let’s import UsersModule into AppModule.

In the example above, we have imported UsersModule into AppModule imports.

Now, if we restart our development server and navigate to http://localhost:3000/users, we should see a JSON response with our list of users.

Run the NestJs application in command line
NesJs users endpoint result

Check the output in the above screenshot when you open the url in browser.

Conclusion

NestJs is a powerful framework for building scalable, server-side applications. In this beginner’s guide, we provided an overview of NestJs and its key features, including its architecture, modules, and controllers. We also walked through the process of setting up a basic NestJs application and creating a simple API endpoint.

If you are interested in learning more about NestJs, we recommend checking out the official NestJs documentation, which provides detailed information on the framework’s features and capabilities.

New JavaScript Features In ES2022 That You Should Know

JavaScript Map: Simplify Data Manipulation

Leave a Reply

Your email address will not be published. Required fields are marked *