Question

我有一个canActivate（警卫队），正在检查加载的变量以查看队列是否已加载。

但是，我现在需要检查多个队列加载变量（boolean），以查看它们是否都已加载。然后，我将需要调度动作。

    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）来检查其布尔值并激活后卫？

Answer 1

我将创建一个选择器，而不是七个不同的选择器。看起来像这样：

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;
  }),
}

然后在您的组件中，您只需选择一个：

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

通过ngrx select检查守卫多个值

1 个答案: