sd-cycle

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle',
  
  things: [
    { id: 1, name: 'a' },
    { id: 2, name: 'b' },
    { id: 3, name: 'c' }
  ]
});

application.template.hbs

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

{{#sc-cycle height=70 items=things as |item|}}
	{{item.name}}
{{/sc-cycle}}

<hr />
{{outlet}}

sc-cycle.component.js

import Ember from 'ember';

const {
  computed
} = Ember;

export default Ember.Component.extend({
  currentItemIndex: 0,
  height: 50,
  transition: true,
  
  circularItems: computed('items', function() {
 		return this.get('items').concat(this.get('items').objectAt(0))
  }),
  
  currentItem: computed('currentItemIndex', function() {
    return this.get('items').objectAt(this.get('currentItemIndex'));
  }),
  
  currentOffset: computed('currentItemIndex', function() {
    return this.get('currentItemIndex') * this.get('height');
  }),
  
  inlineStyleHeight: computed('height', function() {
    const string = `height: ${this.get('height')}px`;
    console.log(`string: ${string}`);
  	return new Ember.Handlebars.SafeString(`height: ${this.get('height')}px`);  
  }),
  
  inlineStyleTop: computed('currentOffset', function() {
    return new Ember.Handlebars.SafeString(`top: -${this.get('currentOffset')}px`);

  }),
  
  actions: {
    updateIndex() {
      const index = this.get('currentItemIndex');
      const nextIndex = (index + 1) % this.get('circularItems.length');
      if(nextIndex === 0) {
      	this.set('transition', false);
        this.set('currentItemIndex', nextIndex);
        Ember.run.next(this, function () {
        	this.set('transition', true);
        	this.set('currentItemIndex', nextIndex + 1);
        });
      }
      else {
      	this.set('transition', true);
        this.set('currentItemIndex', nextIndex);
      }
    	this.set('currentItemIndex', nextIndex);
    }
  }
});

sc-cycle.template.hbs

<p>Current Item Index: {{currentItemIndex}}</p>
<p>Current Offset: {{currentOffset}}</p>
<button {{action "updateIndex"}}>Update Index</button>
<br />
<br />
<div class="sd-cycle" style={{inlineStyleHeight}}>
	<div class="sd-cycle__items {{if transition 'sd-cycle__items--transition'}}" style={{inlineStyleTop}}>
    {{#each circularItems as |item| }}
      <div class="sd-cycle__item" style={{inlineStyleHeight}}>
        {{yield item}}
      </div>
    {{/each}}
	</div>
</div>

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

.sd-cycle {
	overflow: hidden;
  position: relative;
  border: 1px solid blue;
}
.sd-cycle__items--transition {
  transition: top 1s ease-out;
}
.sd-cycle__items {
  position: absolute;
  width: 100%;
}
.sd-cycle__item {
 	background: #ececec 
}

twiddle.json

{
  "version": "0.4.11",
  "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.debug.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"
  }
}