Data Transfer Objects for NestJS

Introduction

Welcome to the @super-nest/data-transfer-objects package! This library provides an efficient and structured approach to managing Data Transfer Objects (DTOs) in your NestJS applications. It enhances the process of defining, organizing, and using DTOs, ensuring data consistency and improving maintainability across your codebase.

Features

• Automated Metadata Generation: Automatically extracts and stores metadata for DTO properties to streamline API documentation and validation.
• Seamless Integration: Works seamlessly with @nestjs/swagger for API and validation metadata.
• Nested Structures: Handles nested DTO structures, allowing you to manage complex data hierarchies with ease.
• Custom Property Options: Supports custom property definitions with enhanced options, including type definitions, titles, descriptions, and more.

Installation

To install the package, run the following command:

$ npm install @super-nest/data-transfer-objects @nestjs/swagger

Usage

Step 1: Import the Module

import { Module } from '@nestjs/common';
import { DataTransferObjectModule } from '@super-nest/data-transfer-objects';

@Module({
    imports: [DataTransferObjectModule.forRoot()],
})
export class AppModule {}

Step 2: Define Your DTOs You can use SuperApiProperty to fit with @super-nest or ApiProperty if you only get metadata.

import { SuperApiProperty, SuperDTO } from '@super-nest/data-transfer-objects';

@SuperDTO()
export class CreateUserDto {
    @SuperApiProperty({ type: String, description: 'User name' })
    //or @ApiProperty({ type: String, description: 'User name' })
    name: string;

    @SuperApiProperty({
        type: String,
        description: 'Email user',
        required: true,
    })
    // or @ApiProperty({ type: String, description: 'Email user', required: true })
    email: string;
}

Step 3: Use DTOs in Your Services

import { Injectable } from '@nestjs/common';
import { DataTransferObjectService } from '@super-nest/data-transfer-objects';
import { CreateUserDto } from './create-user.dto';

@Injectable()
export class UserService {
    constructor(private readonly dtoService: DataTransferObjectService) {}

    async createUser(createUserDto: CreateUserDto) {
        const dtoMetadata = await this.dtoService.findOne(CreateUserDto.name);
        // Use dtoMetadata as needed
        // {
        //     "name": "CreateUserDto",
        //     "form": {
        //         "name": {
        //             "title": "name",
        //             "type": "string",
        //             "description": "User name"
        //         },
        //         "email": {
        //             "title": "email",
        //             "type": "string",
        //             "description": "Email user",
        //             "required": true
        //         }
        //     }
        // }
    }
}

Example: Using Nested DTOs with @SuperDTO

In scenarios where your DTO contains nested objects, you can define and use nested DTOs seamlessly with @SuperDTO. Below is an example illustrating how to handle nested structures like SEOTagDto. Step 1: Import the Module

import { SuperDTO, SuperApiProperty } from '@super-nest/data-transfer-objects';

@SuperDTO()
export class SEOTagDto {
    @SuperApiProperty({
        type: String,
        description: 'The title of the SEO tag',
        default: 'Default SEO Title',
    })
    title: string;

    @SuperApiProperty({
        type: String,
        description: 'The description of the SEO tag',
        default: 'Default SEO Description',
    })
    description: string;
}

Step 2: Use the Nested DTO in a Parent DTO The parent DTO (CreatePostDto) includes the nested SEOTagDto as a property. The library will automatically handle the nested structure and metadata.

import { SuperDTO, SuperApiProperty } from '@super-nest/data-transfer-objects';
import { Type } from 'class-transformer';
import { ValidateNested, IsOptional } from 'class-validator';
import { SEOTagDto } from './seo-tag.dto';

@SuperDTO()
export class CreatePostDto {
    @SuperApiProperty({
        type: String,
        description: 'The name of the post',
        default: 'Post Title',
    })
    name: string;

    @SuperApiProperty({
        type: SEOTagDto,
        description: 'SEO tag information for the post',
        title: 'SEO Tag',
        required: true,
        default: {
            title: 'Post SEO Title',
            description: 'Post SEO Description',
        },
    })
    @ValidateNested()
    @Type(() => SEOTagDto)
    seoTag: SEOTagDto;
}

Step 3: Retrieve Metadata for the Nested DTO Using the DataTransferObjectService, you can retrieve the full metadata, including nested structures.

import { Injectable } from '@nestjs/common';
import { DataTransferObjectService } from '@super-nest/data-transfer-objects';
import { CreatePostDto } from './create-post.dto';

@Injectable()
export class PostService {
    constructor(private readonly dtoService: DataTransferObjectService) {}

    async getPostDtoMetadata() {
        const dtoMetadata = await this.dtoService.findOne(CreatePostDto.name);
        console.log(dtoMetadata);
        // Metadata Output:
        // {
        //     "name": "CreatePostDto",
        //     "form": {
        //         "name": {
        //             "title": "name",
        //             "type": "string",
        //             "description": "The name of the post",
        //             "default": "Post Title"
        //         },
        //         "seoTag": {
        //             "title": "SEO Tag",
        //             "type": "object",
        //             "description": "SEO tag information for the post",
        //             "default": {
        //                 "title": "Post SEO Title",
        //                 "description": "Post SEO Description"
        //             },
        //             "form": {
        //                 "title": {
        //                     "title": "title",
        //                     "type": "string",
        //                     "description": "The title of the SEO tag",
        //                     "default": "Default SEO Title"
        //                 },
        //                 "description": {
        //                     "title": "description",
        //                     "type": "string",
        //                     "description": "The description of the SEO tag",
        //                     "default": "Default SEO Description"
        //                 }
        //             }
        //         }
        //     }
        // }
    }
}

Contact

For any questions or issues, please reach out to the author:

• Hoang Cong Nhut Vy
• GitHub Profile
• Linkedin