Used in blog post

Observables-example.js

import { Observable } from 'rxjs';

const greeting$ = new Observable(observer => {
    const clear = setInterval(() => {
        observer.next('Hello, there');
    }, 1000);
    // Need to handle the interval here, otherwise you'll end up in a infinitely firing observable.
});

greeting$.subscribe(res => {
    console.log(res);
})