jQuery plugin to wrap every x items with element y

jquery.wrapInChunks.js

  // Expose the Array.reverse() method on jQuery objects
  $.fn.reverse = [].reverse;
  /**
   * takes a jQuery collection and wraps each x items with element y
   * kinda nasty looking though
   * example: $('.foo').children().wrapInChunks('<div class="bar" />', 3);
   * wraps every 3 children of .foo in div.bar
   * NOTE: Needs a way to distinguish the wrapper from the wrapped elements,
   * ergo, wrapping classless, IDless DIVs with classless, IDless DIVs will error out
   */
  jQuery.fn.wrapInChunks = function(html, chunkSize) {
      chunkSize = chunkSize || 1;
      var items = this.get(),
          collection = this,
          rows = [],
          cur = rows[0] = html,
          amount = this.length,
          helper = function(times, $el) {
            var $that = $el,
                $html = $(html),
                classes = $html.attr('class'),
                myId = $html.attr('id'),
                checker = $html[0].nodeName,
                classes2,
                myId2,
                checker2;
            checker += classes.length ? '.' + classes.split(' ').join('.') : '';
            checker += myId && myId.length ? '#' + myId : '';
            while (times--) {
              $that = $that.prev();
              classes2 = $that.attr('class');
              myId2 = $that.attr('id');
              checker2 = $that[0].nodeName;
              checker2 += classes2.length ? '.' + classes2.split(' ').join('.') : '';
              checker2 += myId2 && myId2.length ? '#' + myId2 : '';
              if (!$that.is(checker) && collection.filter(checker2).length) {
                $el = $el.add($that[0]);
              }
            }
            return $el;
          };
      return this.each(function(i, el) {
        var $this = $(this);
        i++;
        if (i % chunkSize == 0) {
          var num = chunkSize,
              $that = $this;
          $this = helper(num, $that);
          $this.reverse().wrapAll(html);
        }
        else {
          if (i == amount) {
            var num = i % chunkSize -1,
                $that = $this;
            $this = helper(num, $that);
            $this.reverse().wrapAll(html);
          }
        }
      });
  };

seriously need a better way to check if we are still dealing with elements in the original collection
ergo, get rid of (!$that.is(checker) && collection.filter(checker2).length) and everything that's got to do with it