simple-rx.js

var a = Rx.Observable.create(function(observer) {
    setInterval(function() {
        var curA = Math.floor((Math.random() * 100) + 1);
        console.log("Current value of a " + curA);
        observer.onNext(curA);
    }, 3000);
});
var b = 0;
a.subscribe(function(val) {
    b=val+1;
    console.log("Current value of b " +b);
});