docs: function(arr, num, padding) {
      var result = [], len = arr.length, group;
      if (len === 0 || num === 0) return arr;
      if (isUndefined(num)) num = 1;
      if (isUndefined(padding)) padding = null;
      simpleRepeat(ceil(len / num), function(i) {
        group = arr.slice(num * i, num * i + num);
        while(group.length < num) {
          group.push(padding);
        }
        result.push(group);
      });
      return result;
    }