New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  click() {
		this.sendAction('doToggle');
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
	bar: false,
	actions: {
    doToggle() {
			// alert('foo');
			let bar = this.get('bar');
			console.log('setting bar to :: ', !bar);
      this.set('bar', !bar);
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>
{{#if bar}}
	<h1>Show</h1>
{{else}}
	<h1>Hide</h1>
{{/if}}
{{my-component doToggle=(action "doToggle")}}

templates.components.my-component.hbs

<button>foo</button>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}