New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  queryParams: ['foo'],
  
  foo: 'bar',
  
  actions: {
    setToNull() {
      this.set('foo', null);
    },
    setToUndefined() {
      this.set('foo', undefined);
    },
    setToFalse() {
      this.set('foo', false);
    },
    setToBar() {
      this.set('foo', 'bar');
    },
    setToBaz() {
      this.set('foo', 'baz');
    }
  }
});

templates.application.hbs

<button {{action "setToNull"}}>Set to null</button>
<button {{action "setToUndefined"}}>Set to undefined</button>
<button {{action "setToFalse"}}>Set to false</button>
<button {{action "setToBar"}}>Set to bar</button>
<button {{action "setToBaz"}}>Set to baz</button>

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"
  }
}