question: How to validate nested arrays when the elements are from different classes?

[elad30300]

I use nestjs with class-validator, and I have the following case:

• Two classes with same field name that has different types:

class A {
  @IsDefined()
  field: number;
}

class B {
  @IsDefined()
  field: string;
}

• Third class that has array of elements from types A or B, my problem is how to validate each array member against its own class:

class C {
  @ValidateNested({ each: true })
  @Type(I_DON'T_KNOW_WHAT_TO_DO_HERE)
  array: (A | B)[];
}

How can I validate the array?

Thanks ahead!

[Cha-Shao]

same

request:

{
    "nickname": "NickName",
    "sign": "Sign",
    "content": "Content",
    "links": {
        "github": "github",
        "youtube": "youtube",
    }
}

DTO

class LinksDto {
  @IsString()
  @MaxLength(39)
  @IsNotEmpty()
  public github: string

  @IsString()
  @MaxLength(39)
  @IsNotEmpty()
  public youtube: string
}

class AccountsDto {
  @IsString()
  @MaxLength(16)
  @IsNotEmpty()
  public nickname: string;

  @IsString()
  @MaxLength(60)
  public sign: string;

  @IsString()
  @MaxLength(150)
  public content: string;

  @ValidateNested()
  public links: LinksDto
}

Logs

An instance of AccountInfoDto has failed the validation:
 - property links.github has failed the following constraints: whitelistValidation
 - property links.youtube has failed the following constraints: whitelistValidation

errors[0].children

[
  ValidationError {
    target: {
      github: 'github',
      youtube: 'youtube',
    },
    value: 'github',
    property: 'github',
    children: undefined,
    constraints: { whitelistValidation: 'property github should not exist' }
  },
  ValidationError {
    target: {
      github: 'github',
      youtube: 'youtube',
    },
    value: 'youtube',
    property: 'youtube',
    children: undefined,
    constraints: { whitelistValidation: 'property youtube should not exist' }
  },
]

response: property github should not exist, property youtube should not exist

[liudichen]

Maybe this will work. @Cha-Shao

import { Type } from 'class-transformer';

  @ValidateNested()
  @Type(()=>LinksDto)
  links: LinksDto

[smoothbronx]

@elad30300 Hi, I came across your question. Quite a lot of time has passed since the creation, but maybe it will be useful to someone in the future.

class C {
    @ValidateNested({ each: true })
    @Type(null, {
        keepDiscriminatorProperty: true,
        discriminator: {
            property: 'type',
            subTypes: [
                {
                    name: 'A',
                    value: A,
                },
                {
                    name: 'B',
                    value: B,
                },
            ],
        },
    })
  array: (A | B)[];
}

[aminetrabelsi]

@smoothbronx I have this error Argument of type 'null' is not assignable to parameter of type '((type?: TypeHelpOptions | undefined) => Function) | undefined'