Cubit handling exceptions vs Cubit handling results

exceptions_example.dart

/// Exceptions example
class AppVersioningCubit extends Cubit<AppVersioningState> {
  AppVersioningCubit(this.appVersioningService)
      : super(const AppVersioningState.initial());

  final AppVersioningServiceContract appVersioningService;

  /// Calls appVersioningService.getAppVersion to fetch current app version.
  /// Then, pass appVersion to validateAppVersionMethod.
  Future<void> getAndValidateAppVersion() async {
    emit(
      const AppVersioningState.loading(),
    );

    try {
      final appVersion = await appVersioningService.getAppVersion();
      final appVersionValidationResult =
          await appVersioningService.validateAppVersion(appVersion);
      emit(
        appVersionValidationResult.map(
          forceUpgrade: (result) => AppVersioningState.forceUpgrade(
            currentVersion: appVersion,
            upgradeInformation: result.upgradeInformation,
          ),
          availableUpgrade: (result) => AppVersioningState.availableUpgrade(
            currentVersion: appVersion,
            upgradeInformation: result.upgradeInformation,
          ),
          // Esta no existiria ya que se trataria como una exception
          // unexpectedError: (result) =>
          //     AppVersioningState.errorValidatingAppVersion(
          //   currentVersion: appVersion,
          // ),
        ),
      );
    } on AppVersioningServiceException catch (exception) {
      exception.when(
        getAppVersionError: (exception, stackTrace) =>
            emitErrorGettingAppVersion(exception),
        validateAppVersionError: () => emitErrorValidatingAppVersion(
          exception.appVersion,
          exception,
        ),
      );
    }
  }

  @visibleForTesting
  void emitErrorGettingAppVersion(Object? exception) => emit(
        AppVersioningState.errorGettingAppVersion(
          exception: exception,
        ),
      );
  @visibleForTesting
  void emitErrorValidatingAppVersion(
    AppVersion appVersion,
    Object? exception,
  ) =>
      emit(
        AppVersioningState.errorValidatingAppVersion(
          currentVersion: appVersion,
          exception: exception,
        ),
      );
}

results_example.dart

/// Results example
class AppVersioningCubit extends Cubit<AppVersioningState> {
  AppVersioningCubit(this.appVersioningService)
      : super(const AppVersioningState.initial());

  final AppVersioningServiceContract appVersioningService;

  /// Calls appVersioningService.getAppVersion to fetch current app version
  ///
  /// Depending on the result, decides to validate in case of success or emits
  /// an error state in case of failure.
  Future<void> getAndValidateAppVersion() async {
    emit(
      const AppVersioningState.loading(),
    );
    // Fetches app Validation
    final appVersionResult = await appVersioningService.getAppVersion();

    return appVersionResult.map<FutureOr<void>>(
      success: (success) => validateAppVersion(success.appVersion),
      failure: (failure) => emitErrorGettingAppVersion(failure.exception),
    );
  }

  /// Validates appVersion previously obtained and emits a valid state for it
  @visibleForTesting
  Future<void> validateAppVersion(AppVersion appVersion) async {
    final appVersionValidationResult =
        await appVersioningService.validateAppVersion(appVersion);

    emit(
      appVersionValidationResult.map(
        forceUpgrade: (result) => AppVersioningState.forceUpgrade(
          currentVersion: appVersion,
          upgradeInformation: result.upgradeInformation,
        ),
        availableUpgrade: (result) => AppVersioningState.availableUpgrade(
          currentVersion: appVersion,
          upgradeInformation: result.upgradeInformation,
        ),
        unmaintained: (_) => AppVersioningState.unmaintainedApp(
          currentVersion: appVersion,
        ),
        usingLastVersion: (_) => AppVersioningState.noUpdatesAvailable(
          currentVersion: appVersion,
        ),
        unexpectedError: (result) =>
            AppVersioningState.errorValidatingAppVersion(
          currentVersion: appVersion,
        ),
      ),
    );
  }

  @visibleForTesting
  void emitErrorGettingAppVersion(Object? exception) => emit(
        AppVersioningState.errorGettingAppVersion(
          exception: exception,
        ),
      );
}