How to make an asynchronous timer using rxjs?

Question

Angular

The main idea is to make a timer that will run every n seconds after all requests have completed. Because the project is written in Angular 2, then it should be done in rxjs
Here's what I tried to do:

export interface IAsyncTimer {
  timerObservable: Observable<any>
  observables: Array<Observable<any>>
}

@Injectable()
export class AsyncTimer {
  private timers: Map<number, IAsyncTimer> = new Map<number, IAsyncTimer>();

  public addTimer(time: number,
                  func: Observable<any>) {
    let timer = this.timers.get(time);

    if (!!timer) {
      timer.observables.push(func);
    }
    else {
      let observable = Observable.interval(time)
                                 .timeInterval(),
          timer      = {
            timerObservable: observable,
            observables    : [func]
          };
      timer.timerObservable.switchMap(Observable.forkJoin.apply(Observable, timer.observables)).subscribe(() => {});
      this.timers.set(time, timer);
    }
  }
}

For example, on a page I have several components. Each of them stores the logic for obtaining data within itself. They need to be updated every certain number of seconds. I inject the service and add the request to the queue