Ember.js each loop : compare current index data with previous index data

In ember.js each loop, How can I access the data of the previous index inside the current loop?

   //compare current min with previous min

     <div>Something</div>

  

I know I can create a helper to store the previous index data inside the template scope, but is there any template only way? If not, what will be the most elegant way using a helper?