Yeaaah

controllers.application.js

import Ember from 'ember';

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

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
    return ['Hello', 'Hi', 'Hey', 'Goodbye'];
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

{{#each model as |title index|}}
<div>{{title}}</div>
{{my-component showArrow=(if (eq index 3) true)}}
{{/each}}

templates.components.my-component.hbs

{{yield}}
{{#if showArrow}}Show arrow{{/if}}

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",
    "ember-truth-helpers": "1.0.0"
  }
}