Simple observable/observer in rxjs - rxjs

Question

I've tried 2 different ways to setup an observer/observable to make this code work:
Setup #1:
var xObserver;
var xObservable = Rx.Observable
.create(observer => xObserver = observer)
.publish()
.refCount();
Setup #2:
var xObserver = Rx.Subject.create();
var xObservable = x;
Usage
xObserver.next('foo'); // no subscription yet, so nothing should happen
xObservable.subscribe(v => console.log(v)); // pipe values to console
xObserver.next('bar'); // push another value, should go to console
My expectation is for nothing to happen when "foo" is pushed to the observer, and for only "bar" to be shown on the console.
With "Setup #1" I get an error "TypeError: Cannot read property 'next' of undefined" which makes sense because no observer has subscribed yet so the xObserver is not initialized yet.
With "Setup #2" I get an error "TypeError: xObserver.next is not a function".
What am I doing wrong?

Answer 1

Use:
let xObs = new Rx.Subject();
When you use .create you have to supply an Observer, see the docs for details.
Another pitfall might be the version, in version < 5 there is only .onNext():
xObs.onNext("myData");
https://jsfiddle.net/mzkmuewf/
In version > 5, there is only .next():
xObs.next("myData");
https://jsfiddle.net/j1sksg7q/