New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  classNameBindings: [
    'isSelected'
  ],
  isSelected: false,
  
  actions: {
    toggleSelected() {
      this.toggleProperty('isSelected');
    }
  }
});

styles.app.css

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

.is-selected {
  background-color: yellow;
}

templates.application.hbs

{{my-component}}

templates.components.my-component.hbs

<button {{action 'toggleSelected'}}>with actions</button>

or <button {{action (action (mut isSelected) (if isSelected false true))}}>closure actions</button>

twiddle.json

{
  "version": "0.10.4",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.7.0",
    "ember-data": "2.7.0",
    "ember-template-compiler": "2.7.0"
  },
  "addons": {}
}