code: function($item, focus, preventScroll) {
              if (!this.settings.multi) {
                  this.deselectAll();
              }
  
              this.$first = this.$last = $item;
              this.first = this.last = this.getItemIndex($item);
  
              if (focus) {
                  this.setFocusableItem($item);
                  this.focusItem($item, preventScroll);
              }
  
              this._selectItems($item);
          }
docs: Select Item