NestJS CLI: Practical Code Examples for Generating Components

NestJS provides a powerful CLI (Command Line Interface) tool that helps developers generate boilerplate code for various components in a NestJS application. Here are some practical examples of how to use the NestJS CLI to generate code for different components:

Generating a new NestJS application

To generate a new NestJS application, run the following command:

nest new my-app

This command will create a new folder called `my-app` and generate the basic structure of a NestJS application inside it, including a `src` folder with a `main.ts` file, a `package.json` file, and a `node_modules` folder.

Generating a new module

To generate a new module, run the following command:

nest generate module users

This command will generate a new folder called `users` inside the `src` folder and create a `users.module.ts` file inside it. The `users.module.ts` file will contain a basic module definition, including an `@Module()` decorator and an `exports` array.

Generating a new controller

To generate a new controller, run the following command:

nest generate controller users

This command will generate a new `users.controller.ts` file inside the `src/users` folder. The `users.controller.ts` file will contain a basic controller definition, including an `@Controller()` decorator and some basic route handlers.

Generating a new service

To generate a new service, run the following command:

nest generate service users

This command will generate a new `users.service.ts` file inside the `src/users` folder. The `users.service.ts` file will contain a basic service definition, including an `@Injectable()` decorator and some basic methods.

Generating a new middleware

To generate a new middleware, run the following command:

nest generate middleware auth

This command will generate a new `auth.middleware.ts` file inside the `src/middleware` folder. The `auth.middleware.ts` file will contain a basic middleware definition, including an `@Injectable()` decorator and a `use()` method.

Generating a new resource

To generate a new resource, run the following command:

nest generate resource users

The `nest generate resource` command is used to generate a complete set of files and folders for a new resource in your application, including a `users.controller.ts`, a `users.service.ts`, a `user.module.ts`, and a data transfer object (DTO) class. This command can help speed up the development process by creating the basic scaffolding for a new resource, allowing developers to focus on implementing the business logic for the new feature.

The generated code follows best practices for building a scalable and maintainable NestJS application, including dependency injection, separation of concerns, and modular architecture. By using this command, developers can ensure that their new resources are consistent with the rest of their applications and adhere to the conventions and patterns used by the NestJS community.

Generating a new provider

To generate a new provider, run the following command:

nest generate provider logger

This command will generate a new `logger.provider.ts` file inside the `src/providers` folder. The `logger.provider.ts` file will contain a basic provider definition, including an `@Injectable()` decorator and some basic methods.

Generating a new interceptor

To generate a new interceptor, run the following command:

nest generate interceptor logging

This command will generate a new `logging.interceptor.ts` file inside the `src/interceptors` folder. The `logging.interceptor.ts` file will contain a basic interceptor definition, including an `@Injectable()` decorator and an `intercept()` method.

Generating a new guard

To generate a new guard, run the following command:

nest generate guard auth

This command will generate a new `auth.guard.ts` file inside the `src/guards` folder. The `auth.guard.ts` file will contain a basic guard definition, including an `@Injectable()` decorator and a `canActivate()` method.

These are just a few examples of the many different types of components that can be generated using the NestJS CLI. By using the CLI to generate boilerplate code for these components, developers can save time and ensure that their code follows the best practices and conventions used in NestJS.