New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  // Create a fake "model" from a POJO
  presence: Ember.Object.extend({
    isOnline: Ember.computed.equal('availability', 'ONLINE'),
    isOffline: Ember.computed.not('isOnline')
  })
  // This is the POJO
  .create({
    availability: 'OFFLINE',
  }),
  
  actions: {
    toggle() {
      this.set('presence.availability', 'ONLINE');
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<button {{action "toggle"}}>Toggle</button><br />
Availability: {{presence.availability}}<br />
IsOnline: {{if presence.isOnline "true" "false"}}
<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"
  }
}