How to use action classes in NestJs

First, we'll create an actions folder in our project's root directory. Inside this folder, we'll create a file called create-post.action.ts with the following code:

import { Injectable } from '@nestjs/common';
import { Post } from './post.entity';
import { PostRepository } from './post.repository';

@Injectable()
export class CreatePostAction {
  constructor(private postRepository: PostRepository) {}

  async execute(data: any): Promise<Post> {
    const post = new Post();
    post.title = data.title;
    post.body = data.body;
    return await this.postRepository.save(post);
  }
}

In this code, we're creating a new CreatePostAction class that has a constructor that injects a PostRepository instance. We're also defining an execute method that takes in some data and returns a Promise<Post>.

Inside the execute method, we're creating a new Post instance, setting its title and body properties based on the data provided, and then saving it to the PostRepository.

Now that we've created the CreatePostAction, we'll use it in a controller. We'll assume that we have a PostsController that handles HTTP requests related to posts.

import { Controller, Post, Body } from '@nestjs/common';
import { CreatePostAction } from './actions/create-post.action';

@Controller('posts')
export class PostsController {
  constructor(private createPostAction: CreatePostAction) {}

  @Post()
  async create(@Body() data: any) {
    return await this.createPostAction.execute(data);
  }
}

In this code, we're injecting the CreatePostAction instance into the PostsController constructor. We're also defining a create endpoint that uses the @Post decorator and takes in some data from the HTTP request body.

Inside the create method, we're calling the execute method of the CreatePostAction instance, passing in the data from the HTTP request body. This will create a new Post instance and save it to the database.

Overall, using action classes can help make your code more modular and maintainable by separating business logic from controllers. By encapsulating specific actions in separate classes, you can reuse them across different controllers or applications, and also make your code more testable.

Using Action Classes in NestJS for Better Code Separation and Reusability

mark vachi ・ Apr 14 '23

#webdev #programming #typescript #nestjs