Wrap ChangeNotifier with an AsyncNotifier

[gazialankus]

I am given a ChangeNotifier and I would love to use it as a first class citizen in my Riverpod app that uses generator and the general approach in the latest docs.

I thought I could wrap it with an AsyncNotifier in which every notifyListeners call of the ChangeNotifier would trigger a state change. AsyncNotifier since its initialization is also async.

The ChangeNotifier in question is SessionManager from Serverpod btw. Here's what I wrote but didn't test, do you think this is a good approach in wrapping a ChangeNotifier?

@Riverpod(keepAlive: true)
class AuthSession extends _$AuthSession {
  SessionManager? _sessionManager;

  @override
  FutureOr<Raw<SessionManager>> build() async {
    final existing = _sessionManager;
    if (existing != null) {
      existing.removeListener(listener);
    }

    final sessionManager = SessionManager(
      caller: ref.read(clientProvider).modules.auth,
    );

    _sessionManager = sessionManager;
    await sessionManager.initialize();
    sessionManager.addListener(listener);
    return sessionManager;
  }

  void listener() {
    final sessionManager = _sessionManager;
    if (sessionManager != null) {
      state = AsyncValue.data(sessionManager);
    }
  }
}

I did the removing listener from the existing one part just in case I ref.invalidate it at some point.

The part that I'm not sure is setting the state using the exact same instance once again, not sure if it will cause a refresh or will be ignored.

Please let me know what you think. It would be nice to hear if you have a better way of wrapping a ChangeNotifier.

[gazialankus]

I just tested it and it works just fine 😊. I guess this is how you wrap a ChangeNotifier in the latest Riverpod.

Feels much better than providing a ChangeNotifier instance and listening to it myself.

The listening bit is encapsulated within the AsyncNotifier and I get to use it the way I expect.

[gazialankus]

It seems this is a better way to wrap ChangeNotifier with an AsyncNotifier. Thanks to @ shreemanarjun in X I realized I should use ref.onDispose.

@Riverpod(keepAlive: true)
class AuthSession extends _$AuthSession {
  @override
  FutureOr<Raw<SessionManager>> build() async {
    ref.onDispose(() {
      state.valueOrNull?.dispose();
    });

    return SessionManager(
      caller: ref.read(clientProvider).modules.auth,
    )
      ..initialize()
      ..addListener(
        () {
          final existing = state.valueOrNull;
          if (existing != null) {
            state = AsyncValue.data(existing);
          }
        },
      );
  }
}