escape html safe

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: Ember.computed(function() {
    return '<h6>someString</h6>';
  }),
    appName1: Ember.computed(function() {
    return Ember.String.htmlSafe('<h2>someString</h2>');
  })

});

templates.application.hbs

{{appName}}
<br>
{{appName1}}
<br>
{{outlet}}
<br>
<br>

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"
  }
}