redux-observable - 如何在单个Redux可观察的史诗中等待/屈服于多个 Action ？

Question

我有一个redux Saga，每次发送“WATCHLIST_FETCH_REQUEST”时，它都会运行三种不同的 Action :

function* watchFetchWatchlist() {
  yield takeLatest('WATCHLIST_FETCH_REQUEST', fetchWatchlist);
}


function* fetchWatchlist() {
  const activity = 'ACTIVITY_FETCH_WATCHLIST';
  yield put(
    addNetworkActivity(activity) // Action 1: enables a global loading indicator before request is made
  );
  const { response, error } = yield call(
    api.fetchWatchlist // make an API request
  );
  yield put(
    removeNetworkActivity(activity) // Action 2: removes the above global loading indicator after request completes
  );
  if (response) {
    yield put(
      updateUserWatchlist(response) // Action 3a: updates Redux store with data if response was successful
    );
  } else {
    yield put(
      watchlistFetchFailed(error) // Action 3b: updates Redux store with error if response failed
    );
  }
}

这个传奇的流程本质上是同步的。必须首先运行操作1才能设置应用程序的全局加载状态。当网络事件完成时，操作2必须在操作1之后并且在API响应返回之后才能运行，以删除全局加载状态。

我对redux-observable还是很陌生，但是我一直在努力探索如何将这个传奇转化为史诗。这里有两个目标:

依次执行操作，而不是并行运行

在单个史诗中执行这些操作/流程(触发类型:'WATCHLIST_FETCH_REQUEST'时会踢开)

您如何通过redux-observable实现此目标？谢谢!

Answer 1

我在这里将部分对话拼凑在一起，从而找到了问题的答案:https://github.com/redux-observable/redux-observable/issues/62

我最终得到了一些类似的东西:

import { concat as concat$ } from 'rxjs/observable/concat';
import { from as from$ } from 'rxjs/observable/from';
import { of as of$ } from 'rxjs/observable/of';


export const fetchWatchlistEpic = (action$) => {
  const activity = 'ACTIVITY_FETCH_WATCHLIST';

  return action$.ofType('WATCHLIST_FETCH_REQUEST')
    .switchMap(() =>
      concat$(
        of$(addNetworkActivity(activity)),
        from$(api.fetchWatchlist())
          .map((data) => Immutable.fromJS(data.response))
          .switchMap((watchlist) =>
            of$(
              updateUserWatchlist(watchlist),
              removeNetworkActivity(activity),
            )
          )
      )
    );
};

尝试顺序运行多个操作时， concat和 of似乎是首选操作符。