pausable observable RxJS

switchMap-approach.ts

import { Subject, NEVER, interval } from 'rxjs';
import { switchMap, materialize, dematerialize } from 'rxjs/operators';

const source = interval(1000);
const pauser = new Subject();

// switch between source and 'NEVER' depending on our 'control' pauser
pauser
  .pipe(
    switchMap(paused => paused ? NEVER : source.pipe(materialize())),
    dematerialize()
  )
  .subscribe(console.log);

pauser.next(true); // pause
pauser.next(false); // resume