New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  classNames: ['toggle'],
  classNameBindings: ['isOn'],
  
  click () {
    this.onChange(!this.get('isOn'))
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  actions: {
    onChange (value) {
      this.set('isOn', value)
    }
  }
});

styles.app.css

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

.toggle {
  width: 50px;
  height: 20px;
  background-color: red;
  position: relative;
}

.slider {
  position: absolute;
  width: 20px;
  height: 18px;
  top: 1px;
  left: 1px;
  background-color: blue;
  transition: left 0.5s;
}

.toggle.is-on .slider {
  left: calc(100% - 21px);
}

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{my-component
  isOn=isOn
  onChange=(action 'onChange')
}}
<br>
<br>

templates.components.my-component.hbs

<div class='slider' />

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"
  }
}