ember-html

controllers.application.js

import Ember from 'ember';

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

helpers.get-a-cat.js

import Ember from 'ember';

export function getACat(params/*, hash*/) {
  return Ember.String.htmlSafe(`<img src="http://thecatapi.com/api/images/get?format=src&type=gif">`);
}

export default Ember.Helper.helper(getACat);

templates.application.hbs

<h1> Oh hai :) </h1>

{{get-a-cat}}

<br>

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"
  }
}