Enhance a deferred promise to have finally/catch methods and state

enhanced-deferred.js

import Ember from "ember";

export default function () {
  var deferred = Ember.Deferred.create(),
    promise = new Ember.RSVP.Promise(function(resolve, reject) {
      deferred.then(
        function () { promise.state = "resolved"; resolve.apply(this, arguments); },
        function () { promise.state = "rejected"; reject.apply(this, arguments); }
      );
    });

  promise.state = "pending";
  promise.resolve = deferred.resolve.bind(deferred);
  promise.reject = deferred.reject.bind(deferred);

  return promise;

}