New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  foo: true,
  bar: true,
  
  actions: {
    toggle(key) {
      this.toggleProperty(key);
    }
  }
});

templates.application.hbs

<button {{action "toggle" "foo"}}>
  Toggle foo
</button>
<button {{action "toggle" "bar"}}>
  Toggle bar
</button>

<br>

{{#with foo bar as |_foo _bar|}}
  {{_foo}}
  {{_bar}}
{{/with}}

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"
  }
}