为啥我得到“UnhandledPromiseRejectionWarning：错误：未定义类型错误。确保提供显式类型”即使在我指定了类型之后？

Posted 2023-03-08

【中文标题】为啥我得到“UnhandledPromiseRejectionWarning：错误：未定义类型错误。确保提供显式类型”即使在我指定了类型之后？

【英文标题】：Why I get "UnhandledPromiseRejectionWarning: Error: Undefined type error. Make sure are providing an explicit type" even after I have specified type?为什么我得到“UnhandledPromiseRejectionWarning：错误：未定义类型错误。确保提供显式类型”即使在我指定了类型之后？

【发布时间】：2021-09-09 07:35:20

【问题描述】：

create 方法运行良好。没有错误。但我需要一种方法来一次插入大量记录。 这就是我尝试使用 createQueryBuilder 的原因。

它说未定义类型错误的原因是什么？我已经将类型定义为布尔值。

这是我的解析器

@Resolver(() => Vehicle)
export class VehicleResolver 
  constructor(private vehicleService: VehicleService) 

  @Mutation(() => Vehicle,  name: 'createVehicle' )
  create(@Args('vehicleInput') vehicle: VehicleCreateDTO) 
    return this.vehicleService.create(vehicle);
  

  @Mutation(() => Boolean,  name: 'createVehicleBulk' )
  async createVehicleBulk(@Args('vehiclesInput') vehicles: [VehicleCreateDTO]) 
    const res = await this.vehicleService
      .createBulk(vehicles)
      .catch((err) => console.log(err));
    if (res) return true;
    else return false;
  

这是我的服务

@Injectable()
export class VehicleService 
  constructor(
    @InjectRepository(Vehicle) private vehicleRepo: Repository<Vehicle>,
  ) 

  create(vehicle: VehicleCreateDTO): Promise<Vehicle> 
    const vcl = this.vehicleRepo.create(vehicle);
    return this.vehicleRepo.save(vcl);
  

  async createBulk(vehicles: VehicleCreateDTO[]): Promise<InsertResult> 
    const res = await this.vehicleRepo
      .createQueryBuilder()
      .insert()
      .into('vehicle')
      .values(vehicles)
      .execute();
    return res;
  

我想保存一个 VehicleCreateDTO 类型的对象数组。但我收到以下错误。

(node:11464) UnhandledPromiseRejectionWarning: Error: Undefined type error. Make sure you are providing an explicit type for the "createBulk" (parameter at index [0]) of the "VehicleResolver" class.
    at Object.reflectTypeFromMetadata (E:\COL\backend\vehicle-service-insert\node_modules\@nestjs\graphql\dist\utils\reflection.utilts.js:15:15) 
    at E:\COL\backend\vehicle-service-insert\node_modules\@nestjs\graphql\dist\decorators\args.decorator.js:17:78
    at E:\COL\backend\vehicle-service-insert\node_modules\@nestjs\graphql\dist\schema-builder\storages\lazy-metadata.storage.js:36:44
    at Array.forEach (<anonymous>)
    at LazyMetadataStorageHost.load (E:\COL\backend\vehicle-service-insert\node_modules\@nestjs\graphql\dist\schema-builder\storages\lazy-metadata.storage.js:36:26)
    at GraphQLSchemaFactory.<anonymous> (E:\COL\backend\vehicle-service-insert\node_modules\@nestjs\graphql\dist\schema-builder\graphql-schema.factory.js:37:57)
    at Generator.next (<anonymous>)
    at E:\COL\backend\vehicle-service-insert\node_modules\@nestjs\graphql\node_modules\tslib\tslib.js:117:75
    at new Promise (<anonymous>)
    at Object.__awaiter (E:\COL\backend\vehicle-service-insert\node_modules\@nestjs\graphql\node_modules\tslib\tslib.js:113:16)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:11464) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 2)
(node:11464) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

【问题讨论】：

您找到解决方案了吗？

【参考方案1】：

您的输入类型参数的符号似乎是错误的。此外，如果我仔细观察，错误消息似乎具有误导性

...类型为“createBulk”（索引 [0] 处的参数） “VehicleResolver”类...

但是在您的解析器中，您只有 createVehicle 和 createVehicleBulk 的突变，所以我认为错误是 createVehicleBulk 突变。

只是改变：

  @Mutation(() => Boolean,  name: 'createVehicleBulk' )
  async createVehicleBulk(@Args('vehiclesInput') vehicles: [VehicleCreateDTO]) 
    const res = await this.vehicleService
      .createBulk(vehicles)
      .catch((err) => console.log(err));
    if (res) return true;
    else return false;
  

到

  @Mutation(() => Boolean,  name: 'createVehicleBulk' )
  async createVehicleBulk(@Args( name: 'vehiclesInput', type: () => [VehicleCreateDTO]) vehicles: VehicleCreateDTO[]) 
    const res = await this.vehicleService
      .createBulk(vehicles)
      .catch((err) => console.log(err));
    if (res) return true;
    else return false;
  

我遇到了类似的问题，answer 帮助我找到了解决方案