“typeof globalThis”类型的参数不能分配给“EntryService”类型的参数

Question

我正在尝试将我的服务传递给我传递给方法装饰器的类的实例。

这里是服务：

@Injectable()
export class EntryService {
    constructor(
        @InjectRepository(EntryEntity)
        private readonly entryRepository: Repository<EntryEntity>,
        @InjectRepository(ImageEntity)
        private readonly imageRepository: Repository<ImageEntity>,
        private readonly awsService: AwsService,
        private readonly connection: Connection,
        private readonly categoriesService: CategoriesService,
        private readonly cacheService: CacheService,
        private readonly usersService: UserService,
        private readonly imagesService: ImagesService,
        private readonly notificationService: NotificationsService,
    ) {}

    @RecordEntryOperation(new CreateOperation(this))
    public async create(createEntryDto: CreateEntryBodyDto): Promise<Entry> {
      const queryRunner = this.connection.createQueryRunner();
      await queryRunner.connect();
      await queryRunner.startTransaction();
      try {
        await queryRunner.commitTransaction();
        // more code
      } catch (err) {
        await queryRunner.rollbackTransaction();
      } finally {
        await queryRunner.release();
      }
    }
}

这里的事情是我需要在传递给RecordEntryOperation 装饰器的那个类中使用EntryService。

装饰器（尚未完全实现）：

export const RecordEntryOperation = (operation: Operation) => {
    return (target: object, key: string | symbol, descriptor: PropertyDescriptor) => {
        const original = descriptor.value;
        descriptor.value = async function(...args: any[]) {
            const response = await original.apply(this, args);
            console.log(`operation.execute()`, await operation.execute());
            return response;
        };
    };
};

CreateOperation 类如下所示（尚未完全实现）：

export class CreateOperation extends Operation {
    constructor(public entryService: EntryService) { super(); }

    public async execute(): Promise<any> {
        return this.entryService.someEntryServiceOperation();
    }
}

我得到的错误如下：

Argument of type 'typeof globalThis' is not assignable to parameter of type 'EntryService'.
  Type 'typeof globalThis' is missing the following properties from type 'EntryService': entryRepository, imageRepository, awsService, and 53 more.

我不完全理解这个错误是关于什么的。我怀疑这意味着传递给CreateOperation 类的this 并没有通过依赖注入器将所有这些依赖注入到服务中。

我尝试了不同的方法，但无济于事。好像我不完全明白发生了什么。

有什么想法吗？

那么构建代码的正确方法是什么？

Answer 1

问题出在下面一行：

@RecordEntryOperation(new CreateOperation(this))

this 并不像您预期​​的那样引用EntryService 的实例，而是引用globalThis（this 实际上是指当前模块），因此出现错误。您可以做的是稍微更改您的 Operation-class 并将 entryService 传递给 execute 方法。

export class CreateOperation extends Operation {
    constructor() { super(); }

    public async execute(entryService: EntryService): Promise<any> {
        return entryService.someEntryServiceOperation();
    }
}

然后你可以在你的装饰器中做以下事情：

export const RecordEntryOperation = (OperationType: typeof CreateOperation) => {
    return (target: object, key: string | symbol, descriptor: PropertyDescriptor) => {      
        const operation = new OperationType(); 
        const original = descriptor.value;
        descriptor.value = async function(...args: any[]) {
            const response = await original.apply(this, args);
            console.log(`operation.execute()`, await operation.execute(this));
            return response;
        };
    };
};

然后使用它：

@RecordEntryOperation(CreateOperation)
public async create(createEntryDto: CreateEntryBodyDto): Promise<Entry> { .. }