New Twiddle

components.shopping-item.js

import Ember from 'ember';

export default Ember.Component.extend({
  tagName: 'li',
  
  item: null
});

controllers.application.js

import Ember from 'ember';

const Items = [
  {
    name: 'Apples',
  	completed: false
  }, {
    name: 'Toothbrush',
    completed: false
  }, { 
    name: 'Baked Beans',
    completed: false
  }
];

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  items: Items,
  
  actions: {
  	toggleCompletion(item) {
      let currentState = item.completed;
      Ember.set(item, 'completed', !currentState)
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<ul>
	{{#each items as |item|}}
		{{shopping-item
    	item=item
    	onclick=(action "toggleCompletion")}}
	{{/each}}
 </ul>
<br>

templates.components.shopping-item.hbs

<span onclick={{action onclick item}}>
	{{#if item.completed}}
		<del>{{item.name}}</del>
 	{{else}}
  	{{item.name}}
 	{{/if}}
</span>

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"
  }
}