New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  bar: "bar_initial",

  foo: Ember.computed('bar', {
    set(key, value) {
      return `setter(${value})`;
    },
    get(key) {
      return "foo_initial";
    },
  }),
  
  actions: {
    setBar() {
      this.set('bar', Math.random());
    },
    setFoo() {
      this.set('foo', Math.random());
    },
  }
});

templates.application.hbs

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

<p>
  <button onclick={{action 'setBar'}}>Set</button>

  bar={{bar}}
</p>

<p>
  <button onclick={{action 'setFoo'}}>Set</button>
  foo={{foo}}
</p>

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}