Handler

Handler function for BLoC.
Has an extended API closures that are triggered by successful and unsuccessful processing of the main closure.

Usage

1. Prepare states, that contains ApiError, ConnectionError and UnknownError states:

sealed class State {
  const State();
}

final class LoadingState extends State {
  const LoadingState();
}

final class SuccessState extends State {
  const SuccessState({required this.profile});

  final Profile profile;
}

final class ApiErrorState extends State {
  const ApiErrorState();
}

final class ConnectionErrorState extends State {
  const ConnectionErrorState();
}

final class UnknownErrorState extends State {
  const UnknownErrorState();
}

2. Prepare BLoC and put handle method inside methods:

class ProfileBloc extends Bloc<Event, State>
    with BlocHandlerMixin<Event, State, ApiErrorState, ConnectionErrorState> {
  ProfileBloc({required Repository repository})
    : _repository = repository,
      super(const LoadingState()) {
    on<Event>(
      (event, emit) => switch (event) {
        SomeEvent() => _getProfile(event, emit),
      },
    );
  }

  final Repository _repository;

  @override
  State get defaultApiErrorState => const ApiErrorState();
  @override
  State get defaultConnectionErrorState => const ConnectionErrorState();
  @override
  State get defaultUnknownErrorState => const UnknownErrorState();

  Future<void> _getProfile(Event event, Emitter<State> emit) =>
      handle(emit, () async {
        final profile = await _repository.getProfile();
        emit(SuccessState(profile: profile));
      });
}

API

fallback - flag that determines whether to emit to the initial state;
onError - callback triggered for any error;
getApiErrorState - closure for ApiError, in case a different state is needed, different from the default state;
getConnectionErrorState - closure for ConnectionError, in case a different state is needed, different from the default state;
getUnknownErrorState - closure for unkwnonwn error, in case a different state is needed, different from the default state;
getFallbackState - closure for fallback state, in case a different state is needed, different from the initial state;
onFinally - callback triggered in the finally section.

Additional information

For more details see example project.
And feel free to open an issue if you find any bugs or errors or suggestions.