import {timer} from "rxjs/observable/timer";

let observable = timer(1, 1000); //timer will emit an event each second

let subscribtion = observable.subscribe((data) => {
  //do stuff for each tick of stream data
  console.log(data);
}, (reason) => {
  //when there was an error while watching observable
}, () => {
  //do stuff when stream is complete
});

//when you need to unsubscribe from this events you can call
subscribtion.unsubscribe();