New Twiddle

controllers.application.js

import Ember from 'ember';
import { task } from 'ember-concurrency';
function change() {
  this.set('appName', 'blam')
}
export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  foo: Ember.computed('appName',function () { 
    // this.set('appName', 'blam')
    this.get('bar').perform()
  }),
  bar: task(function * () {
    // this.set('appName', 'blam')
    Ember.run.scheduleOnce('afterRender',this, change)
  })
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
{{foo}}
<br>
<br>
{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.13.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3",
        "ember-concurrency": "0.8.14"
  }
}