New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Observe and Chain Demo',
  clicks: 0,
  someProp: 'undefined',
  
  bindOnInitAndPropChange: Ember.on('init', function() {
 		this.set('someProp', `Initialized. I see ${ this.get('clicks') } clicks.`); 
    Ember.addObserver(this, 'clicks', null, function() {
      this.set('someProp', `Observed, I now see ${ this.get('clicks') } clicks.`);
    });
  }),
  
  actions: {
  	incrementClicks() {
    	this.incrementProperty('clicks');  
    }
  }
});

templates.application.hbs

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

<p>Property: {{ someProp }}</p>
<p><b>Clicks:</b> {{ clicks }}</p>
<button {{action "incrementClicks"}}>Add a Click!</button>
<br>
<br>

twiddle.json

{
  "version": "0.8.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.5.1",
    "ember-data": "2.5.2",
    "ember-template-compiler": "2.5.1"
  }
}