SPA RxJS based router

router.js

var hashChangeEvent = Rx.Observable.fromEvent(window, 'hashchange');

var hash = location.hash;
var hashSubject = new Rx.BehaviorSubject(hash);

hashSubject.subscribe(function(hash) {
    router(hash.replace('#', ''));
});
hashChangeEvent.subscribe(function(e) {
    hashSubject.onNext(location.hash);
});

function router(hash) {
  console.log('Do magic stuff to %s', hash)
}

On page load the hash is passed to router(), when ever the hash changes, the new hash is passed to the router. hashChangeEvent also knows the old hash