Parent effects are setting providers for children

[stupidawesome]

The way effects are provided it's currently not possible to scope them to the host due to a bug in the NodeInjector, which is not respecting injector flags that are passed to it.

Issue tracked here

[stupidawesome]

To workaround this issue, I am checking if the service exists in a parent injector and comparing its value to the one injected in the current injector when effects are run. In some cases this might throw an error if there are dangling providers that were provided in the parent injector but not used.

@Injectable()
export class MyEffects() {
    constructor(elementRef: ElementRef) {}

    @Effect() someEffect() {}
}

@NgModule({
    providers: [MyEffects] // dangling provider
})
export class AppModule

@Component({
    providers: [Effects, MyEffects]
})
export class AppComponent {}

MyEffects injects tokens that are not available to AppModule. We check the parent by injecting it, so it throws an error which we can't recover from. To fix this error, remove the dangling provider.

[stupidawesome]

Decorator API has been deprecated, composition API does not suffer from this issue.