如何使用@ngrx/store获取State对象的当前值？

在调用Web服务之前，我的服务类需要从状态中获取一个名为 dataForUpdate 的属性。目前，我是这样做的：

constructor(public _store: Store < AppState > ,
  public _APIService: APIService) {

  const store$ = this._store.select('StateReducer');

  .../...

  let update = this.actions$.filter(action => action.type == UPDATE)
    .do((action) => this._store.dispatch({
      type: REDUCER_UPDATING,
      payload: action.payload
    })) **
    * GET STATE ** *= => .mergeMap(action => store$.map((state: AppState) => state.dataForUpdate).distinctUntilChanged(),
      (action, dataForUpdate) {
        return {
          type: action.type,
          payload: {
            employee: action.payload,
            dataForUpdate: dataForUpdate
          }
        };
      }) *
    AND CALL API *= => .mergeMap(action => this._APIService.updateEmployee(action.payload.employee, action.payload.dataForUpdate),
      (action, APIResult) => {
        return {
          type: REDUCER_UPDATED
        }
      })
    .share();


  .../...

  let all = Observable.merge(update, ....);
  all.subscribe((action: Action) => this._store.dispatch(action));

}

我正在使用angular2-store-example (https://github.com/ngrx/angular2-store-example/blob/master/src/app/users/models/users.ts)作为指南。
我想知道是否存在更好（更清晰）的方法？
实时示例：https://plnkr.co/edit/WRPfMzPolQsYNGzBUS1g?p=preview