Hierarchical injector

Hi, in order to make more reusable code, I would like to create a module which use a component which is not a part of this module, nor include in an imported module. The component will be inject by the ApplicationModule (main module). It seems that this is not supported?

Example: AuthenticationModule has different controllers which use a UserService dependency. UserModule also has different controllers which use a UserService dependency.

Depending on application, the UserService may be implemented in different way. What I want is defining this in the ApplicationModule for all modules, once for all.

@Module({
    modules: [ AuthenticationModule, UserModule ]
    components: [
        { provide: UserService, useClass: MyCustomUserService }
    ]
})
class ApplicationModule {}

@Module({
    controllers: [],
    components: [ AuthenticationService ],
    exports: [ 
        AuthenticationService
    ]
})
class AuthenticationModule {}

export class AuthenticationService {
    constructor(private userService: UserService) {}
}

I was expecting below code to work (similar to angular), but the userService dependency is not found.

[kamilmysliwiec]

Hi @AurelieV, I made a set of improvements for a dependency injector, so now your example should works fine. Please, update your packages (since ~2.* version @nestjs/core, @nestjs/common etc.) into latest versions.

[AurelieV]

The problem is I do not want my two modules being dependant on each others. AuthenticationService can be use without UserModule. UserService is not part of UserModule