New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  classNameBindings: ['isNegative:is-negative:is-positive'],
  
  isNegative: Ember.computed(function() {
    return this.value < 0;
  })
});

controllers.application.js

import Ember from 'ember';

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

helpers.my-helper.js

import Ember from 'ember';

export function myHelper(params/*, hash*/) {
  return "<div>123</div>";
}

export default Ember.Helper.helper(myHelper);

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}

{{{my-helper 12345}}}

{{my-component value=1}}

{{my-component value=-1}}
<br>
<br>

templates.components.my-component.hbs

{{value}}

twiddle.json

{
  "version": "0.10.7",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.10.0",
    "ember-data": "2.10.0",
    "ember-template-compiler": "2.10.0",
    "ember-testing": "2.10.0"
  },
  "addons": {}
}