New Twiddle

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
	actions = {
    hideModal:function(option)
    {
      	if(option)
        {
          	alert("Yes clicked.")
        }
      	else
        {
          	alert("No clicked")
        }
      	this.toggleProperty("showmodal")
    }
  }
}

styles.app\.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}
span
{
  	display:block;
  	width:100px;
  	height:100px;
  background : red;
  margin-top:100px;
}

templates.application\.hbs

{{input type="checkbox" checked=showmodal}}
{{#if showmodal}}
		<span>
    <button {{action "hideModal" 1}}>Yes</button>
    <button {{action "hideModal" 0}}>No</button>
    </span>
{{/if}}

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"
  }
}