Object length

controllers.application.js

import Ember from 'ember';
const {Object: EmObject} = Ember;

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  stuff: EmObject.create({
    'something' : [1,2,3]
  })
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
{{get (get stuff 'something') 'length'}}
<br>
{{outlet}}
<br>
<br>

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": {}
}