New Twiddle

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
	queryParams: ['category'],
  appName:'E',
  category: null,
  
   posts: [ { title: "Descartes was Nice", category: "philosophy" },
           { title: "Wittgenstein is mad smart", category: "philosophy" },
           { title: "Ember is going 3.0", category: "programming" },
           { title: "Rails ist kaput", category: "programming" },
           { title: "Asimov is real good", category: "scifi" },
           { title: "Fantasy is not scifi", category: "scifi" }
          ],
  
  filteredPosts: function() {
    const posts = this.get('posts');
  	const category = this.get('category');
    if (category) {
      return this.get('posts').filterBy('category', category);
    } else {
      return posts;
    }
	}.property('category', 'model')
});

application.template.hbs

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

{{#link-to (query-params category="philosophy")}}Philosophy{{/link-to}}
{{#link-to (query-params category="programming")}}Programming{{/link-to}}
{{#link-to (query-params category="scifi")}}Science Fiction{{/link-to}}
{{#link-to (query-params category=null)}}All{{/link-to}}

<ul>
{{#each filteredPosts as |post|}}
	<li>{{post.title}}</li>
{{/each}}
</ul>

{{outlet}}

twiddle.json

{
  "version": "0.4.10",
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/1.13.11/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember-template-compiler.js"
  }
}