如何创建一个redux可观察史诗,在做任何事情之前等待2个动作

正如@jayphelps在评论中指出的,根据您是否需要访问各种事件以及事件是否必须严格排序,有两种变体。因此,以下各项都应适用:

1) 严格的命令不关心事件:

action$
  .ofType(FIRST_ACTION)
  .take(1)
  .concat(action$.ofType(SECOND_ACTION).take(1))
  .mapTo({ type: DO_THE_THING_ACTION })

action$
  .ofType(FIRST_ACTION)
  .take(1)
  .concatMap(
    a1 => action$.ofType(SECOND_ACTION).take(1),
    (a1, a2) => ({type: DO_THE_THING_ACTION, a1, a2})
  )

3) 非严格命令(做或不做)关心事件

Observable.forkJoin(
  action$.ofType(FIRST_ACTION).take(1),
  action$.ofType(SECOND_ACTION).take(1),
  // Add this lambda if you *do* care
  (a1, a2) => ({type: DO_THE_THING_ACTION, a1, a2})
)
// Use mapTo if you *don't* care
.mapTo({type: DO_THE_THING_ACTION})

这是redux可观察对象的外观:

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/zip';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/take';


function doTheThing(action$) {
  return Observable
     // waits for all actions listed to complete
    .zip(action$.ofType(FIRST_ACTION).take(1), 
         action$.ofType(SECOND_ACTION).take(1),
     )

    // do the thing
    .map(() => ({ type: DO_THE_THING_ACTION }));
}