为什么nestjs不能解析依赖？

Question

所以我有一个 Nest 应用程序，但被困在一个非常基本的问题上。

我需要在PlaceService[中使用PlaceVerificationRequestService 但无法在不收到以下错误的情况下正确注入它：

Nest can't resolve dependencies of the PlaceService (PlaceRepository, ClientService, ?). Please make sure that the argument dependency at index [2] is available in the PlaceModule context.

我的方法是遵循与我在导入和注入 ClientService 到 [=30= 时相同的风格]PlaceService 但它仍然不起作用，我不知道为什么。

这是我的代码。

place.module.ts

@Module({
  imports: [
    MikroOrmModule.forFeature({
      entities: [Place, Client, PlaceVerificationRequest],
    }),
  ],
  providers: [PlaceService, ClientService, PlaceVerificationRequestService],
  controllers: [PlaceController],
  exports: [PlaceService],
})

place-验证-request.module.ts

@Module({
  imports: [
    MikroOrmModule.forFeature({
      entities: [PlaceVerificationRequest, Client, Place],
    }),
  ],
  providers: [PlaceVerificationRequestService, ClientService, PlaceService],
  controllers: [PlaceVerificationRequestController],
  exports: [PlaceVerificationRequestService],
})

place.service.ts

@Injectable()
export class PlaceService {
  constructor(
    @InjectRepository(Place)
    private readonly placeRepo: EntityRepository<Place>,
    private readonly clientService: ClientService,
    private readonly reqService: PlaceVerificationRequestService,
  ) {}

感觉就像我错过了就在我鼻子前面的东西，因为它感觉很基本，但我似乎无法发现它。有人知道吗？谢谢

Answer 1

5 小时后，诀窍是……阅读文档。

Nest can't resolve dependencies of the <provider> (?). Please make sure that the argument <unknown_token> at index [<index>] is available in the <module> context.

Potential solutions:
- If <unknown_token> is a provider, is it part of the current <module>?
- If <unknown_token> is exported from a separate @Module, is that module imported within <module>?
  @Module({
    imports: [ /* the Module containing <unknown_token> */ ]
  })

If the unknown_token above is the string dependency, you might have a circular file import.

（必须承认他们可以提出更清晰的错误消息）

所以基本上问题是 PlaceService 被注入到 PlaceVerificationRequestService 中，而 PlaceVerificationRequestService 被注入到 PlaceService 中，所以诀窍是使用 forwardRef:

PlaceVerificationRequestService

@Inject(forwardRef(() => PlaceService))
private readonly placeService: PlaceService,

地点服务

@Inject(forwardRef(() => PlaceVerificationRequestService))
private readonly reqService: PlaceVerificationRequestService,

为什么nestjs不能解析依赖？

Why cant nestj resolve dependencies?

javascript

nestjs

mikro-orm