Angular APP_INITIALIZER with NgRx Effects

app.initializer.ts

/**
 * App Initializer with Effects
 */

export function initApplication(store: Store<AppState>) {
  return () =>
    new Promise(resolve => {
      const loaded$ = new Subject();
      store.dispatch(new LoadSystem());
      store
        .select((state:AppState) => state.isLoaded)
        .pipe(takeUntil(loaded$))
        .subscribe(loaded => {
          if (loaded) {
            loaded$.next();
            resolve();
          }
        });
    });
}