style

components.my-component.js

import Ember from 'ember';

const {
  computed,
  get
} = Ember;

export default Ember.Component.extend({
  attributeBindings: ['style'],
  style: computed('isFoo', function() {
    let style = get(this, 'isFoo') ? 'color: red' : 'color: blue';
    return style.htmlSafe();
  }),
  
  isFoo: false,
  
  click() {
  	this.toggleProperty('isFoo');
	}
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#my-component}}
	hello
{{/my-component}}
{{outlet}}
<br>
<br>

templates.components.my-component.hbs

{{yield}}

twiddle.json

{
  "version": "0.8.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.5.1",
    "ember-data": "2.5.2",
    "ember-template-compiler": "2.5.1"
  }
}