how to merge requests into one observable angular 2

Question

There are several requests in subscribe and the same number is obtained at the output due to which the traffic leak. I tried flatMap, map. Maybe who come across and know how to solve?

Observable.fromEvent(document.querySelector('employees'), 'input')
      .debounceTime(500)
      .distinctUntilChanged()
      .subscribe((event) => {
          this.searchFilter(Value);
      });