父组件中服务器的初始状态

最好将其置于路由器防护装置中=>canActivate()

检查数据是否存在于存储中;否则调度负载数据

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

checkStore(): Observable<boolean> {
  return this.store.select(fromStore.getDataLoaded).pipe(
    tap(loaded => {
      if (!loaded) {
        this.store.dispatch(new fromStore.LoadDataCollection());
      }
    }),
    filter(loaded => loaded),
    take(1)
    );
}