New Twiddle

controllers.application\.js

import Controller from '@ember/controller';
import { tracked } from '@glimmer/tracking';
import { action, computed, set } from '@ember/object';

export default class ApplicationController extends Controller {
	@tracked configuration = {
  	numbers: [1, 2, 3, 4]
  };

	// this doesn't work
	// get evens() {
	// return this.configuration.numbers.filter(num => num % 2 === 0)
	// }

	// this works
	@computed('configuration.numbers')
	get evens() {
  	return this.configuration.numbers.filter(num => num % 2 === 0)
  }


	@action
	updateAppName() {
    this.set('configuration.numbers', [1, 2, 3]);
  }
}

templates.application\.hbs

<div>
	{{this.evens}}
</div>


<button {{on "click" this.updateAppName}}>Clicking this button won't update the title</button>

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"
  }
}