redux - 在 Flutter Redux Epic 中间件中，如何在流变量更改后调度动作？

Question

在 Flutter Redux Epic 中间件中，如何在流变量更改后调度动作？

EpicMiddleware 的一个简单示例：

final allEpics = combineEpics<AppState>([hourglassesStream]);

Firestore firestore = Firestore.instance;


Stream<dynamic> hourglassesStream(
    Stream<dynamic> actions, EpicStore<AppState> store) {
  return Observable(actions)
      .ofType(TypeToken<ConnectToDataSourceAction>())
      .switchMap((ConnectToDataSourceAction requestAction) {
    getHourglasses(action.userId).listen((hourglass) {

      LoadHourglassesHistoryAction(
          hourglass.map(Hourglass.fromEntity).toList());
    });
  });
}

Observable<List<HourglassEntity>> getHourglasses(String userId) {
  return Observable(firestore
      .collection('users')
      .document(userId)
      .collection('hourglassLogs')
      .snapshots()
      .map((snapshot) {
    return snapshot.documents.map((doc) {
      return HourglassEntity(
        doc['completedTime'],
        doc['projectName'],
        doc['userId'],
      );
    }).toList();
  }));
}

在沙漏变量从 observable 更改后，我尝试了一些不同的方法来调度这个LoadHourglassesHistoryAction ，但不调度。是否可以在 Observable 更改后调度一个动作？

使用的包：
redux_epics：^0.10.0 & rxdart：^0.18.0

Answer 1

您必须返回可观察/流，以调度操作

Stream<dynamic> hourglassesStream(
    Stream<dynamic> actions, EpicStore<AppState> store) {
  return Observable(actions)
      .ofType(TypeToken<ConnectToDataSourceAction>())
      .switchMap((ConnectToDataSourceAction requestAction) {
    return getHourglasses(action.id).map((hourglass) =>
     LoadHourglassesHistoryAction(
          hourglass.map(Hourglass.fromEntity).toList())
    );
  });
}