Signal-based reactive data services

[swift axle]

Hello people.

I am trying to architect a new Angular application, and I would like any suggestions on how to utilize the new Signals API to create state management and data services.

I have been using the Data services with rxjs Subjects/BehaviorSubjects pattern for many years successfully, and I would like any info on how to implement something similar using Signals. I understand that I can map observables to Signals and vice-versa, but it seems that this pattern is useful only if you need to adopt signals in an existing project, and cannot afford the effort of re-writing your data/state management.
Maybe I am wrong, but it feels like this isn't the best approach to use Signals.

p.s. I do not want to use any 3d party state management library like ngrx, redux etc

Thanks!

[quasi smelt]

but it seems that this pattern is useful only if you need to adopt signals in an existing project, and cannot afford the effort of re-writing your data/state management
I would disagree with that. As soon as you need to get data in an asynchronous way, RxJS will be a good tool to use.
For example, let's say you want to display the user with the ID passed as input to a component, the easiest way to do that in a clean way would be to do something like

  userId = input.required<string>();
  user: Signal<User | undefined> = toSignal(toObservable(this.userId).pipe(switchMap(id => userService.get(id)));

[swift axle]

Doesn't this look already too complicated to you?
user: Signal<User | undefined> = toSignal(toObservable(this.userId).pipe(switchMap(id => userService.get(id)));

I mean the main selling point of Signals seems to be that state management code would be less complex and easier to read than RxJS. Maybe I am missing something here

[autumn stag]

This looks like normal signal usage

[swift axle]

Why should I use Signals then? Just to ditch the async pipe ?

[quasi smelt]

Yes. And to be able to access the data displayed by the view from inside the component. And be ready for future zoneless apps and signal components. And be able to use computed(), effect(), etc. But sure, signals are not mandatory, since we've been writing Angular apps without them for years.

[quasi smelt]

This isn't really about managing the state. It's about doing multiple asynchronous operations without introducing race conditions, and that's where RxJS shines.