New Twiddle

controllers.application.js

import Ember from 'ember';

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

helpers.render-blocks.js

import Ember from 'ember';

export function renderBlocks(text/*, hash*/) {
  var div = document.createElement('div');
  var classes = ['yellow'];
  div.className = classes.join(' ');
  
  var t = document.createTextNode(text + ' (in DOM)');
  div.appendChild(t);
  
  return div;
}

export default Ember.Helper.helper(renderBlocks);

templates.application.hbs

<style>
  .yellow { background-color: yellow; }
</style>

{{render-blocks "hello"}}

{{render-blocks "goodbye"}}

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": {}
}