TypeError at formatI18nErrors when validating nested array of objects

Hi there,

I always get a TypeError: Cannot convert undefined or null to object\n when using validation method "i18n.validate" from the "I18nService" while validating nested array of objects.

This error does not occur, when the normal "validate" function of the "class-validator" library is used.

Thank you, Heiko

My Dto (Parent)

export class RestrictionCodeDto {

  @IsNotEmpty({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isNotEmptyError') })
  @Validate(hasRestrictionCodeValidLength, { message: i18nValidationMessage<I18nTranslations>('messages.validation.rcLengthError') })
  id: string;

  @IsNotEmpty({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isNotEmptyError') })
  @IsString({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isStringError') })
  @Length(4, 4, { each: true, message: i18nValidationMessage<I18nTranslations>('messages.validation.lengthError') })
  salesOrganization: string;

  @Type(() => Boolean)
  @IsBoolean({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isBooleanError') })
  active: boolean

  @Type(() => Boolean)
  @IsBoolean({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isBooleanError') })
  defectMaingroupRequired: boolean;

  @IsNotEmpty({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isNotEmptyError') })
  @IsString({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isStringError') })
  @Length(7, 7, { message: i18nValidationMessage<I18nTranslations>('messages.validation.lengthError') })
  changedBy: string;

  @IsOptional()
  @Type(() => Date)
  @IsDate({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isDateError') })
  lastChangeOn: Date | null;

  @ValidateNested({each: true})
  @Type(() => RestrictionCodeTextDto)
  texts: RestrictionCodeTextDto [];
}

My Dto (Nested)

export class RestrictionCodeTextDto {

  @IsString({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isStringError') })
  @Length(2, 2, { message: i18nValidationMessage<I18nTranslations>('messages.validation.lengthError') })
  language: string;

  @IsString({ message: i18nValidationMessage<I18nTranslations>('messages.validation.isStringError') })
  @MaxLength(200, { message: i18nValidationMessage<I18nTranslations>('messages.validation.maxLengthError') })
  text: string;
}

My Pipe

@Injectable()
export class RestrictionCodePipe implements PipeTransform {

  constructor(private i18n: I18nService) { }

  async transform(value: any, { metatype }: ArgumentMetadata) {
    const appException: AppException = new AppException(HttpStatus.BAD_REQUEST, []);

    const restrictionCodeDto: RestrictionCodeDto = plainToInstance(metatype, value);

    // this method throws the stack trace
    const errors: I18nValidationError[] = await this.i18n.validate( 
      restrictionCodeDto, { lang: I18nContext.current().lang }
    );

   // processing of errors
  }
}

Stack Trace

{"TypeError: Cannot convert undefined or null to object\n    at Function.keys (<anonymous>)\n    at ...node_modules\\nestjs-i18n\\src\\utils\\util.ts:79:32\n    at Array.map (<anonymous>)\n    at formatI18nErrors (...node_modules\\nestjs-i18n\\src\\utils\\util.ts:64:17)\n    at ...\\node_modules\\nestjs-i18n\\src\\utils\\util.ts:78:22\n    at Array.map (<anonymous>)\n    at formatI18nErrors (...\\node_modules\\nestjs-i18n\\src\\utils\\util.ts:64:17)\n    at I18nService.validate (...\\node_modules\\nestjs-i18n\\src\\services\\i18n.service.ts:361:28)\n    at processTicksAndRejections (node:internal/process/task_queues:95:5)\n    at RestrictionCodePipe.transform (...\\src\\rc-maintenance\\pipes\\restriction-code.pipe.ts:19:43)"}

Originally posted by @heken84 in https://github.com/toonvanstrijp/nestjs-i18n/discussions/630

toonvanstrijp / nestjs-i18n

TypeError at formatI18nErrors when validating nested array of objects #633