New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  a : 'test',
  didRender(){
    let set = this.set
	new Promise(function(resolve, reject) {
  	setTimeout(set, 1000, 'a', 'foo');
	});
  },
  sdlf: Ember.observer('a', function(){console.log(this.a)})
});

components.my-componenta.js

import Ember from 'ember';

export default Ember.Component.extend({
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#my-component as |h|}}
	{{h.component}}
{{/my-component}}
<br>
<br>

templates.components.my-component.hbs

{{yield (hash
	somethingother='test'
  component=(component 'my-componenta' something=a)
  )}}

templates.components.my-componenta.hbs

{{something}}

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}