Enumerable Properties Demo

controllers.application\.js

import Controller from '@ember/controller';
import EmberObject, { computed } from '@ember/object';

const MyObject = EmberObject.extend({
  prop: computed(function() {}),
});

class Foo {
  // getters are not enumerable!, but properties are
   get prop() {
     return;
   }
}

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';

	get info () {
    let foo = MyObject.create();
    return enumerableInfoFor(foo);
  }

	get nativeInfo() {
    let foo = new Foo();
		return enumerableInfoFor(foo);
	}
}

function enumerableInfoFor(obj) {
    let isEnumerable = false;
    
    for (let key in obj) {
      // the long inefficient way of doing getOwnPropertyDescriptor().enumerable
      if (key === 'prop') isEnumerable = true;
    }
    
		return {
      'myObject': obj,
      'Object.keys': Object.keys(obj).join(', '),
      'can be iterated over?': isEnumerable,
      [`'prop' in obj`]: 'prop' in obj,
      ["Object.getOwnPropertyDescriptor"]: Object.getOwnPropertyDescriptor(obj.__proto__, 'prop'), 
    };
}

helpers.stringify\.js

import { helper } from '@ember/component/helper';

export default helper(function stringify([data]/*, hash*/) {
  return JSON.stringify(data, null, 2);
});

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<br>
<br>
EmberObject:
<pre>
{{stringify this.info}}
</pre>

Native Class:
<pre>
{{stringify this.nativeInfo}}
</pre>
<br>
<br>

tests.test-helper\.js

import Application from '../app';
import config from '../config/environment';
import { setApplication } from '@ember/test-helpers';
import { assign } from '@ember/polyfills';
import { start } from 'ember-qunit';

let attributes = {
  rootElement: '#test-root',
  autoboot: false
};
attributes = assign(attributes, config.APP);

let application = Application.create(attributes);
setApplication(application);

start();

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}