ArrayProxy Issue

controllers.application.js

import Ember from 'ember';

const { ArrayProxy, set } = Ember;

const CustomArrayProxy = ArrayProxy.extend({
  willDestroy() {
    set(this, 'content.length', 0);
    set(this, 'content', []);
    set(this, 'length', 0);
    this._super(...arguments);
  }
});

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  init() {
    this._super();
    this.proxyArray = CustomArrayProxy.create({
      content: [
        { name: 'hello' }
      ]
    });
  },
  actions: {
    bam() {
      this.proxyArray.destroy()
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<ul>
Total Items: {{proxyArray.length}}
{{#each proxyArray as |item|}}
  <li>{{item.name}}</li>
{{/each}}
</ul>
<br>
<button {{action "bam"}}>Teardown Proxy Array</button>
{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.14.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "2.18.2",
    "ember-template-compiler": "2.18.2",
    "ember-testing": "2.18.2"
  },
  "addons": {
    "ember-data": "2.18.2"
  }
}