Nest.js can't resolve dependencies

问题

I am trying to use ConfigService in my users.module.ts but I am getting an

Error: Nest can't resolve dependencies of the UsersService (UserRepository, HttpService, ?). Please make sure that the argument ConfigService at index [2] is available in the UsersModule context.

Potential solutions:

If ConfigService is a provider, is it part of the current UsersModule?
If ConfigService is exported from a separate @Module, is that module imported within UsersModule?

I have imported the ConfigModule in my UsersModule but still its not working :(

app.module.ts

@Module({
  imports: [
    ConfigModule.forRoot({
      expandVariables: true,
    }),
    TypeOrmModule.forRoot(),
    UsersModule,
    AuthModule,
  ],
  controllers: [AppController],
  providers: [AppService],
})

export class AppModule {}

users.module.ts

import { ConfigModule } from '@nestjs/config';

@Module({
  imports: [ConfigModule, HttpModule, TypeOrmModule.forFeature([User])],
  controllers: [UsersController],
  providers: [UsersService],
  exports: [UsersService],
})

export class UsersModule {}

users.service.ts

export class UsersService {

 constructor(
    @InjectRepository(User)
    private readonly userRepository: Repository<User>,
    private readonly httpService: HttpService,
    private readonly configService: ConfigService,
  ) {}

}

回答1:

You would still have to declare ConfigService in the providers of users.module.ts. Refer example below.

app.module.ts

@Module({
  imports: [
    ConfigModule.forRoot({
      expandVariables: true,
    }),
    TypeOrmModule.forRoot(),
    UsersModule,
    AuthModule,
  ],
  controllers: [AppController],
  providers: [AppService],
})

export class AppModule {}

users.module.ts

import { ConfigModule } from '@nestjs/config';

@Module({
  imports: [ConfigModule, HttpModule, TypeOrmModule.forFeature([UserRepository])],
  controllers: [UsersController],
  providers: [UsersService, ConfigService],
  exports: [UsersService],
})

export class UsersModule {}

Hope this helps.

Thanks.

回答2:

You got things kinda crossed (I went through the same pain starting out too). Best practice would be to create a custom repository to handle the database logic.

First declare a UserRepository:

@EntityRepository(User)
export class UserRepository extends Repository<User> {

    // add your custom db related method here later..

}

Then in your AppModule you need to declare your entities like so:

@Module({

    imports: [

        TypeOrmModule.forRoot({

            type: 'mysql',
            host: process.env.DB_HOSTNAME || 'localhost',
            port: Number.parseInt(process.env.DB_PORT) || 3306,
            username: process.env.DB_USERNAME || 'root',
            password: process.env.DB_PASSWORD || 'mysql',
            database: process.env.DB_NAME || 'nestjs',
            synchronize: process.env.DB_SYNCHRONIZE === 'true' || true,
            keepConnectionAlive: true,
            entities: [

                User

            ]

        })

...

And then in your UsersModule declare your repository:

import { ConfigModule } from '@nestjs/config';

@Module({
  imports: [ConfigModule, HttpModule, TypeOrmModule.forFeature([UserRepository])],
  controllers: [UsersController],
  providers: [UsersService],
  exports: [UsersService],
})

export class UsersModule {}

来源：https://stackoverflow.com/questions/60182039/nest-js-cant-resolve-dependencies

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nestjs

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