skipUntil
by pointzerotwo
HTML
<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/5.4.3/Rx.js"></script>
JavaScript
const user$ = new Rx.BehaviorSubject(null);
const init$ = new Rx.Subject();
const currentUser$ = user$.skipUntil(init$);
currentUser$.subscribe(val => console.log(val));
user$.next('a')
user$.next('b')
init$.next()
user$.next('c')
user$.next('d')