New Twiddle

components.my-component.js

import Ember from 'ember';

const PositionalParams = {positionalParams: ["thing"]};

let Comp = Ember.Component.extend({
  thing: "meow"
});
Comp.reopenClass(PositionalParams);

export default Comp;

controllers.application.js

import Ember from 'ember';

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

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
{{my-component "from template"}}
{{my-component thing="from template"}}
<br>
{{outlet}}
<br>
<br>

templates.components.my-component.hbs

{{yield}}
Thing value: {{thing}}

twiddle.json

{
  "version": "0.4.6",
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "http://builds.emberjs.com/release/ember.debug.js",
    "ember-data": "http://builds.emberjs.com/release/ember-data.js",
    "ember-template-compiler": "http://builds.emberjs.com/release/ember-template-compiler.js"
  }
}