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:

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

This command will create a new folder called 

 and generate the basic structure of a NestJS application inside it, including a 

To generate a new module, run the following command:

This command will generate a new folder called 

 file will contain a basic module definition, including an 

To generate a new controller, run the following command:

 file will contain a basic controller definition, including an 

 decorator and some basic route handlers.

To generate a new service, run the following command:

 file will contain a basic service definition, including an 

To generate a new middleware, run the following command:

file will contain a basic middleware definition, including an 

To generate a new resource, run the following command:

command is used to generate a complete set of files and folders for a new resource in your application, including a 

, 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.

To generate a new provider, run the following command:

 file will contain a basic provider definition, including an 

To generate a new interceptor, run the following command:

 file will contain a basic interceptor definition, including an 

To generate a new guard, run the following command: 

 file will contain a basic guard definition, including an 

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.

NestJS CLI: Practical Code Examples for Generating Components

Nest.js is a progressive Node.js framework used for building efficient, scalable, and reliable server-side applications. It is built with modern JavaScript and uses TypeScript, which enables type-checking and helps in better code maintainability. TypeORM is a powerful object-relational mapping library that allows developers to easily map their database schemas to TypeScript classes. In this guide, we will learn how to get started with Nest.js and connect a MySQL database to it using TypeORM.

To get started with Nest.js, you first need to install its CLI tool globally on your machine. Open a command prompt or terminal and run the following command:

Once the CLI tool is installed, you can create a new Nest.js project by running the following command:

 with your desired project name. This will create a new Nest.js project with all the required boilerplate code.

In order to use TypeORM and connect to a MySQL database, we need to install a few additional dependencies. Run the following command in your project directory to install them: 

 package provides integration with Nest.js, 

Next, we need to configure the connection to our MySQL database. Open the 

 file in your project root directory and add the following configuration:

-name with your MySQL server details. The entities property specifies the location of our entity files and 

 will synchronize the database schema with our entities on every application launch. 

We now need to create a TypeORM entity that will represent our database table. To do this, we'll use the nest schematics and run the following script: 

. Navigate to the entity-file and replace the code with the following code:

 ensures that the field is an auto-incremented integer value.

Step 6: Add the User as a feature in the UsersModule

In order for us to set up the created feature, we need to import 

 and uses it to specify that it will be managing the 

, which we will create in the next steps.

Step 7: Navigate to the User-controller file

If you decided to generate the resource as an REST API, and to include CRUD logic the 

should in this step have CRUD logic calling the 

 that will return all the users from the database using the 

Step 8: Query from the database with the repository

 method that will return all the users from the database.

is a built-in middleware that helps to validate incoming request payloads against a defined class-validator schema.

When a request is received, ValidationPipe automatically applies the validation rules to the request payload according to the specified class-validator schema. If any validation errors occur, the pipe throws a BadRequestException with the details of the validation errors, which can then be handled by a custom exception filter.

Here is an example of how to add the ValidationPipe globally for all controllers:

This will create a new Nest.js application using the 

 for input validation, and listen on port 3000.

To test the application, run the following command in your project directory: 

This will start the Nest.js application and connect to the MySQL database. You should see a message indicating that the application is running on port 3000. You can then navigate to 

 in your browser to see a list of all the users in the database.

Congratulations, you have now successfully created a Nest.js application and connected it to a MySQL database using TypeORM!

Getting Started with Nest.js and MySQL Database Connection Using TypeORM

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:

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.

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

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.

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

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

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

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:

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

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

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:

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.

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Nest.js

NestJS CLI: Practical Code Examples for Generating Components

Getting Started with Nest.js and MySQL Database Connection Using TypeORM

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

More about Nest.js