Manipulating data from store

I'd like to manipulate the data I get from the store object (this.store.find('...'), etc.), like limiting (I can't just send a limit to the API, since I'm just using fixtures at the moment) or reversing the result.

For limiting I've already tried to implement a limit helper and call it in the each block (#each (limit recentItems 5) ...);

import Ember from 'ember';

export default Ember.Helper.helper(function(params) {
  return params[0].slice(0, params[1]);
});

I don't know exactly why it didn't work, but it seems that the result object is not an array and therefore I'm not able to slice it. Same goes for reverting.

Thanks.