Remove the default value defined in the CreateDto when using the UpdateDto

[sour bough]

In my create DTO, I defined an optional parameter with a default value. However, when using the update DTO, even though I didn't pass that parameter, it still appeared in the controller. How can I prevent this from happening?

import { IsOptional } from 'class-validator';

export class CreateAdminDto {
  readonly username: string;

  @IsOptional()
  readonly firstName?: string | null = 'admin';
}

import { PartialType } from '@nestjs/mapped-types';
import { CreateAdminDto } from './create-admin.dto';

export class UpdateAdminDto extends PartialType(CreateAdminDto) {}

[jovial flare]

likely because the update Dto uses the createDto

export class UpdateAdminDto extends PartialType(CreateAdminDto) {}

basicly means take the CreateAdminDto and make all fields optional then apply that to the UpdateAdminDto

[last island]

PartialType is just a type definition, it does not strip the value at runtime. At runtime, CreateAdminDto is instantiated when UpdateAdminDto is instantiated, therefore firstName has a default value of admin. Use a different DTO. Also, most likely unless it's a very basic CRUD application, the DTO used to Create and the DTO used to Update are not going to match.

[sour bough]

Thank You

[sour bough]

Thank You

[jovial flare]

Glad i could help

[rich prawn]

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[lilac bough]

You can use OmitType to remove properties you don't want in dto.

export class UpdateAdminDto extends PartialType(OmitType(CreateAdminDto, ['firstName'] as const)) {}

See: https://docs.nestjs.com/openapi/mapped-types.
But you can't just remove default value from another dto. You can create new class like they said or redefine the same property without default value.