I'm facing a problem. I have this example repository:

I want to inject RaceService into HeroService because I want to use some methods such as getById.

I follow the documentation described here:

The problems happen when I do next:

At RaceModule I added RaceService as export:

@Module({
  imports: [TypeOrmModule.forFeature([RaceEntity])],
  controllers: [RaceController],
  providers: [RaceService],
  exports: [RaceService],
})

At HeroModule I imported RaceModule:

@Module({
  imports: [RaceModule, TypeOrmModule.forFeature([HeroEntity])],
  controllers: [HeroController],
  providers: [HeroService],
})

At HeroService I added inject for RaceService:

constructor(
    @InjectRepository(HeroEntity)
    private heroRepository: Repository<HeroEntity>,
    private readonly raceService: RaceService,
  ) {
  }

The error appears at the console:

Error: Nest cannot create the module instance. Often, this is because of a circular dependency between modules. Use forwardRef() to avoid it

I try different ways to import the service, including creating a new CommonsModule, also putting a forwardRef into the raceService definition but another error appears:

Nest can't resolve dependencies of the HeroService (HeroEntityRepository, ?). Please make sure that the argument at index [1] is available in the HeroModule context.

Thanks for the help!

I'm facing a problem. I have this example repository: https://github./pillowslept/nest-example

I want to inject RaceService into HeroService because I want to use some methods such as getById.

I follow the documentation described here: https://docs.nestjs./modules

The problems happen when I do next:

At RaceModule I added RaceService as export:

@Module({
  imports: [TypeOrmModule.forFeature([RaceEntity])],
  controllers: [RaceController],
  providers: [RaceService],
  exports: [RaceService],
})

At HeroModule I imported RaceModule:

@Module({
  imports: [RaceModule, TypeOrmModule.forFeature([HeroEntity])],
  controllers: [HeroController],
  providers: [HeroService],
})

At HeroService I added inject for RaceService:

constructor(
    @InjectRepository(HeroEntity)
    private heroRepository: Repository<HeroEntity>,
    private readonly raceService: RaceService,
  ) {
  }

The error appears at the console:

Error: Nest cannot create the module instance. Often, this is because of a circular dependency between modules. Use forwardRef() to avoid it

I try different ways to import the service, including creating a new CommonsModule, also putting a forwardRef into the raceService definition but another error appears:

Nest can't resolve dependencies of the HeroService (HeroEntityRepository, ?). Please make sure that the argument at index [1] is available in the HeroModule context.

Thanks for the help!

• javascript
• node.js
• nestjs

• I made a pull request on your GitHub repo, hopefully you find it helpful. – Jackie McDoniel Commented Jul 27, 2019 at 5:57
• 1 @Juan Wele to SO! As your problem seems to be solved, consider adding it as an answer to your own question. Others might profit from your solution and can also see that your problem is already solved. :-) – Kim Kern Commented Jul 28, 2019 at 22:23

2 Answers 2

With some help I realize that my problem appears because I created a file index.ts at the modules folder (with the idea of export the module names at once), like this:

export { RaceModule } from './race.module';
... others

So, then when I try to import the RaceModule at HeroModule, like this:

import { RaceModule } from 'modules';

My problem appears.

I don't know why but referencing the module import directly from the index.ts file rather than:

import { RaceModule } from 'modules/race.module';

Was the problem of my code.

So, following some remendations, I created some folders and move some files and my project start working as should be.

Thanks for help and hope someone find this helpful.

You need to import module of race module in hero module