code: function () {
              var carousel = this;
              return carousel.get("currentPage") + 1 == carousel.get("numPages") ?
                     carousel.get("numItems") - 1:
                     carousel.get("firstVisible") + carousel.get("numVisible") - 1;
          }
docs: Get the index of the last visible item
  
  @method _getLastVisible
  @protected