API DTO

Purpose

Generate Data Transfer Objects (DTOs) with class-validator decorators, transformation logic, partial DTOs for updates, and response DTOs that exclude sensitive fields.

When to Use

• Creating request/response DTOs
• Adding validation to inputs
• Type-safe API contracts
• Excluding sensitive fields from responses

What It Generates

Directory Structure

apps/api/src/modules/{feature}/dto/
├── create-{entity}.dto.ts
├── update-{entity}.dto.ts
├── {entity}-response.dto.ts
├── list-{entities}.dto.ts
└── index.ts

Patterns Enforced

Validation Decorators

Use class-validator decorators:

• @IsString(), @IsEmail(), @IsUUID(), etc.
• @MinLength(), @MaxLength(), etc.
• Custom validation messages
• @ValidateNested() for nested objects

Transformation

Use class-transformer:

• @Transform() for trimming strings
• @Type() for nested type conversion
• Automatic lowercase for emails

Partial Updates

Update DTOs extend PartialType from @nestjs/swagger:

• All fields optional
• Preserves validation on provided fields

Response DTOs

• Exclude sensitive fields (passwords, tokens)
• Use @Expose() for explicit field control
• Transform dates to ISO strings

Usage Example

/skill api-dto --name=User --fields='email:email,password:password,name:string,isActive:boolean'

Related Files

• API Controller - Controllers using DTOs
• Feature CQRS - Commands/queries with DTOs