yo

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  actions: {
	  yo: function() {
      this.set('yo', !this.get('yo'));
	  }
	}
});

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

.yo {
    opacity: 0;
    transform: translateY(-1em);
    transition: opacity, transform;
}

.yo-yo-yo {
    opacity: 1;
    transform: translateY(0);
}

templates.application.hbs

<button {{action 'yo'}}>yo?</button>
<div class='yo {{if yo 'yo-yo-yo'}}'>yo</div>

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"
  }
}