Is possible filter an Object in Nestjs class-validator?

Question

I have the following class:

export class CreateUserDto {
  @IsEmail()
  email: string;

  @IsNotEmpty()
  password: string;
}

But if i sent to my route the following Object:

{
   "email": "[email protected]",
   "password": "123456789",
   "role": "Admin"
}

when i ran in my back-end console.log(body) the role stay in the object. Its possible filter that Object to automatically remove the role field?

Answer 1

I found an answer. Basically in ur custom validation u can pass a whitelist argument to validate function.

    @Injectable()
export class ValidationPipe implements PipeTransform<any> {
  async transform(value: any, { metatype, type, data }: ArgumentMetadata) {
    if (!metatype || !this.toValidate(metatype)) {
      return await Sanitize(value);
    }

    const object = plainToClass(metatype, value);
    process.env.LOG_REQUESTS === 'true' && console.log(object);
    const errors = await validate(object, { whitelist: true }); // <-- that argument

    if (errors.length > 0) {
      console.log('Validation failed - ' + errors);
      throw new BadRequestException('Input mal formatado.');
    }

    return await Sanitize(object);
  }

  private toValidate(metatype): boolean {
    const types = [String, Boolean, Number, Array, Object];
    return !types.includes(metatype);
  }
}

the whitelist argument will remove all non fields that not exists in Obj class