JS Bin// source http://jsbin.com/todewiz

Stream.js

"use strict";
var Stream = (function () {
    function Stream(val) {
        this._source = new Rx.BehaviorSubject(val);
        this._obs = this._source.asObservable();
        return this._obs;
    }
    return Stream;
}());

Stream.prototype.next = function (val) {
        this._source.next(val);
    };

var s = new Stream('test').subscribe(function (val) { return console.log(val); });

s.next("next test");