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通过NGRX选择检查多个值的保护

angular-guards ngrx-store ngrx rxjs angular

1

prabhat gundepalli · 技术社区 · 8 年前

我有一个canactivate(guard),在这里我检查加载的变量,看看队列是否加载了。

不过,我现在需要检查多个队列加载变量(布尔值),看看它们是否都已加载。那我就得采取行动了。

    canActivate(): Observable<boolean> {
return this.checkStore().pipe(
  switchMap(() => of(true)),
  catchError(() => of(false))
);
}

  checkStore(): Observable<boolean> {
//   Below are the additional booleans I need to check on
//  this.store.select(fromStore.isFirstQueueLoaded);
//  this.store.select(fromStore.isSecondQueueLoaded);
//  this.store.select(fromStore.isThirdQueueLoaded);
//  this.store.select(fromStore.isFourthQueueLoaded);
//  this.store.select(fromStore.isFifthQueueLoaded);
//  this.store.select(fromStore.isSixthQueueLoaded);
//  this.store.select(fromStore.isSeventhQueueLoaded);


  return this.store.select(fromStore.isFirstQueueLoaded)
  // want to check for remaining queues loaded boolean val here
  .pipe(
  tap(loaded => {   
     // need to check for loaded values of all queues
    if (!loaded) {
      this.dispatchActiontoStoreForAllQueue();
    }
  }),
  filter(loaded => loaded)
  );
 }

dispatchActiontoStoreForAllQueue(): void {
this.store.dispatch(new fromStore.LoadFirstQueue({}));
this.store.dispatch(new fromStore.LoadSecondQueue({}));
this.store.dispatch(new fromStore.LoadthirdQueue({}));
this.store.dispatch(new fromStore.LoadFourthQueue({}));
this.store.dispatch(new fromStore.LoadFifthQueue({}));
this.store.dispatch(new fromStore.LoadSixthQueue({}));
this.store.dispatch(new fromStore.LoadSeventhQueue({}));
 }

我们如何结合所有这些NGRX选择(优化方法)检查他们的布尔和激活警卫?

1 回复 | 直到 8 年前

1

Teddy Sterne 8 年前

我将创建一个选择器,而不是七个不同的选择器。这看起来像是:

export const fromStore = {
  areAllQueuesLoaded: createSelector(selectAppState, (state: AppState) => {
    return state.queue1.isLoaded &&
           state.queue2.isLoaded &&
           state.queue3.isLoaded &&
           state.queue4.isLoaded &&
           state.queue5.isLoaded &&
           state.queue6.isLoaded &&
           state.queue7.isLoaded;
  }),
}

然后在组件中,您只需要选择一个:

return this.store.select(fromStore.areAllQueuesLoaded).subscribe(loaded => {   
    this.dispatchActiontoStoreForAllQueue();
});