New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  init: function() {
  	this._super(...arguments);
    
    var firstItem = Ember.Object.create({id: 'first'});
		var secondItem = Ember.Object.create({id: 'second'});
		var collection = Ember.A([ firstItem, secondItem ]);
    
    this.setProperties({ firstItem, secondItem, collection });
	}
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
Has Next? {{has-next firstItem true collection}}<br>
Has Previous? {{has-previous secondItem true collection}}
<hr>
Next: {{get (next firstItem true collection) 'id'}}<br>
Previous: {{get (previous secondItem true collection) 'id'}}
<br>
<br>

twiddle.json

{
  "version": "0.10.5",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.6.0",
    "ember-data": "2.6.0",
    "ember-template-compiler": "2.6.0",
    "ember-testing": "2.8.0"
  },
  "addons": {
  	"ember-composable-helpers": "1.1.2"
  }
}