New Twiddle

controllers.application.js

import Ember from 'ember';
import { isEmpty } from '@ember/utils';
import EmberObject from '@ember/object';
import ObjectProxy from '@ember/object/proxy';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  obj: null,
  
  actions: {
    handleClick(){
    	let obj = ObjectProxy.create({
        content: EmberObject.create({
          size: "test"
        })
      });
      
      this.set('obj', obj);
  		
      console.log(obj,isEmpty(obj));
    } 
  }
});

templates.application.hbs

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

<button {{action "handleClick"}}>Click Me</button>
<br>
<br>
Value: {{obj.size}}

  
<br>
<br>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}