eventaggregator.js

var Rx = require('rx');

function EventAggregator() {
  this._subject = new Rx.Subject(); // Can be ReplaySubject too
}

EventAggregator.prototype.publish = function (type, data) {
  this._subject.onNext( { type: type, data: data });
};

EventAggregator.prototype.listen = function (type) {
  return this._subject.filter(function (x) { x.type === type }).pluck('data').share();
};

EventAggregator.prototype.dispose = function () {
  this._subject.dispose();
};

// Usage
var e = new EventAggregator();

var subscription = e.listen('foo').subscribe(
  function (x) {
    console.log(x);
  });
  
e.publish('foo', 'bar');
// => 'bar'