Demo Poller

poller.ts

import { IParamsObject, ISearchParams } from '@sp-model/globalSearch.model';
import { Observable } from 'rxjs/Observable';
import { timer } from 'rxjs/observable/timer';
import { merge } from 'rxjs/observable/merge';
import { distinctUntilKeyChanged } from 'rxjs/operators/distinctUntilKeyChanged';
import { filter } from 'rxjs/operators/filter';
import { map } from 'rxjs/operators/map';
import { mapTo } from 'rxjs/operators/mapTo';
import { switchMap } from 'rxjs/operators/switchMap';
import { takeUntil } from 'rxjs/operators/takeUntil';

export function somePoller( obs: Observable<any>,
                                     stopPollObservables: Observable<any>[] ): Observable<any> {
  return obs.pipe(
    // allow poll only if searchTerm as value
    filter(( routeParams: IParamsObject ) =>
             routeParams.params.searchTerm &&
             !!routeParams.params.searchTerm.length),
    // take only when params.searchTerm change value
    distinctUntilKeyChanged('params', ( x: ISearchParams, y: ISearchParams ): boolean => {
      return x.searchTerm === y.searchTerm;
    }),
    switchMap(( routeParams: IParamsObject ): Observable<any> => {

      // Poll starting immediately, and then every 5 min interval
      return timer(0, 300000)
        .pipe(
          // pass routeParams in stream instead of interval number
          map(() => routeParams),
          // stop interval when navigating away from deviceManager page
          takeUntil(
            merge(...stopPollObservables)
              .pipe(mapTo(() => 'STOP POLL')), // fyi only
          ),
        );
    }),
  );
}