New Twiddle

components.parent-component\.js

import Component from '@ember/component';
import {computed} from '@ember/object';

export default Component.extend({
  count: 0,
  init() {
    this._super(...arguments);
    console.log('parent');
  },
  
  didInsertElement() {
  	this._super(...arguments);
    console.log('did insert');
  }
  
  isValid: computed('count', function() {
    return this.get('count') > 0;
  }),
  
  actions: {
   	doSomething() {
      this.doSomething();
    }
  },
  
  doSomething() {
    
  },

	doSomething() {
		
  }
})

controllers.application\.js

import Controller from '@ember/controller';

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

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<br>
<br>
{{parent-component}}
<br>
<br>

templates.components.parent-component\.hbs

<button {{action "doSomething"}}>Click me</button>
<div>Count is {{count}}</div>
<div>Count is valid?
	{{#if isValid}}
  	true
    {{else}}
    false
  {{/if}}
</div>

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": "3.12.2",
    "ember-template-compiler": "3.12.2",
    "ember-testing": "3.12.2"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}