module context

controllers.application.js

import mixinInject from 'twiddle/mixins/file';
import Ember from 'ember';
const { Object } = Ember;
const A =5;

export default Ember.Controller.extend(mixinInject, {
  appName: 'Ember Twiddle',
	init() {
		this._super(...arguments);
		console.log(Object.keys, A);
	}
});

mixins.file.js

import Ember from 'ember';
const A =6;

export default Ember.Mixin.create({
  init() { 
    this._super(...arguments);
		Ember.run.later(this, () => {
			console.log(Object.keys);
      console.log(A);
    }, 5000);
  }
});

templates.application.hbs

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

twiddle.json

{
  "version": "0.10.6",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.9.0",
    "ember-data": "2.9.0",
    "ember-template-compiler": "2.9.0",
    "ember-testing": "2.9.0"
  },
  "addons": {}
}