JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/4.1.0/rx.all.js"></script>

JavaScript

function httpRestService ()
{
return Rx.Observable.return('http call executed').delay(2000);
}

var  stream = Rx.Observable.fromEvent(document, 'click');
stream
  .flatMapFirst(() => httpRestService())
  .subscribe((x) => {
  console.log(x);
  })