Inject nestjs service from another module

Question

I've got a PlayersModule and an ItemsModule.

I want to use the ItemsService in the PlayersService.

When I add it by injection:

import { Injectable } from '@nestjs/common';
import { InjectModel } from 'nestjs-typegoose';
import { ModelType, Ref } from 'typegoose';
import { Player } from './player.model';
import { Item } from '../items/item.model';
import { ItemsService } from '../items/items.service';

@Injectable()
export class PlayersService {
    constructor(
        @InjectModel(Player) private readonly playerModel: ModelType<Player>,
        private readonly itemsService: ItemsService){}

I get this nest error :

[Nest] 11592 - 2018-8-13 11:42:17 [ExceptionHandler] Nest can't resolve dependencies of the PlayersService (+, ?). Please make sure that the argument at index [1] is available in the current context.

Both modules are imported in the app.module.ts. Both services are working alone in their module.

Answer 1

You have to export the ItemsService in the module that provides it:

@Module({
  controllers: [ItemsController],
  providers: [ItemsService],
  exports: [ItemsService]
  ^^^^^^^^^^^^^^^^^^^^^^^
})
export class ItemsModule {}

and then import the exporting module in the module that uses the service:

@Module({
  controllers: [PlayersController],
  providers: [PlayersService],
  imports: [ItemsModule]
  ^^^^^^^^^^^^^^^^^^^^^^
})
export class PlayersModule {}

⚠️ Do not add the same provider to multiple modules. Export the provider, import the module. ⚠️