New Twiddle

controllers.application.js

import Ember from 'ember';
import { task, timeout } from 'ember-concurrency';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  fetchResourcesTask: task(function * (resource) {
   yield timeout(1000); 
  }),
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<button onclick={{perform fetchResourcesTask}}> Start </button>
{{fetchResourcesTask.isRunning}}
<br>
{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "2.12.1",
    "ember-concurrency": "0.8.3"
  }
}