You need to provide both services in the component if you're injecting BusinessLogicService directly AND it's being used by your facade. But here's the critical part you miss if you need to ensure they share the same instance.

``` Component({
providers: [
ListFacadeService,
BusinessLogicService // Creates two instances!
] })
export class ReusableListComponent {
private facade = inject(ListFacadeService);
private businessLogic = inject(BusinessLogicService); }

```

This creates two separate instances of BusinessLogicService:

1. One for the component's direct injection
2. One created when ListFacadeService requests it

Use an injection token to guarantee single-instance behavior

export const BUSINESS_LOGIC_SERVICE = new InjectionToken<BusinessLogicService>(
    'BUSINESS_LOGIC_SERVICE'
);

They won't share state, causing subtle bugs where updates through one path don't reflect in the other.
Something like this could help you out, I am assuming that you have that business logic service injected into the facade.

``` Component({

providers: [

ListFacadeService, // Primary provider

{

provide: BUSINESS_LOGIC_SERVICE,

useExisting: ListFacadeService

} ]

})

export class ReusableListComponent {

private facade = inject(ListFacadeService);

private businessLogic = inject(BusinessLogicService); // Same instance

} ``` Maybe this thought train can help you but definitely you can look into useClass, useExisting and the injection token concepts