NgRx

Question

我有一个效果，根据数据返回的内容，我可能希望提交额外的操作。

使用 this post 中的信息，我可以 return 通过以下两个操作...

public getData$ = createEffect(() => this.actions$.pipe(
    ofType(myDataActions.getData),
    map(() => this.isPollingActive = true),
    mergeMap(() =>
      this.myService.getAllData()
        .pipe(
          tap(data => this.previousResultsTimeUtc = data.previousResultsTimeUtc),
          mergeMap(data => [
            currentDayActions.getCurrentShiftSuccess(data.currentDay),
            myDataActions.getDataSuccess(data)
          ]),
            catchError(err => of(myDataActions.getDataFail(err)))
          ))
    ));

然而，理想情况下，我有时只想提交一个动作，

例如

    ...
      mergeMap(data => [
            if (data.currentDay !== undefined) // <-- how to do this
              currentDayActions.getCurrentDaySuccess(data.currentDay),

            myDataActions.getDataSuccess(data.data)
          ]),

所以，如果我得到数据，我只想提交currentDayActions.getCurrentDaySuccess。

当然以上是不正确的语法，但我不太明白如何在此处获取此 "if"。

更新

非常相似的例子是here

试图做同样事情的效果在feature1/state/feature1.effects.ts

Answer 1

一个if else语句就可以了：

public continuePolling$ = createEffect(() =>
    this.actions$.pipe(
      ofType(
        feature1Actions.startPollSuccess,

        takeWhile(() => this.isPollingActive),
        mergeMap(() =>
          this.feature1Service.getData().pipe(
            delay(8000),
            tap(
              data =>
                (this.previousResultsTimeUtc = data.previousResultsTimeUtc)
            ),
            switchMap(data => {
              if (data.currentDay == undefined) {
                return [feature1Actions.getLibrarySuccess(data)];
              } else {
                return [
                  feature1Actions.getCurrentDaySuccess(data.currentDay),
                  feature1Actions.getLibrarySuccess(data)
                ];
              }
            }),
            catchError(err => of(feature1Actions.getLibraryFail(err)))
          )
        )
      )
    )
  );

NgRx - 可选 return 来自效果的一个或两个动作

NgRx - optionally return either one OR two actions from an effect

ngrx-effects

angular

更新