public function setSortableColumns($columns)
    {
        if (!empty($this->columns()->sortable)) {
            $columns = array_merge($columns, $this->columns()->sortable);
        }

        return $columns;
    }
public function setSortableColumns($columns)
    {
        if (!empty($this->columns()->sortable)) {
            $columns = array_merge($columns, $this->columns()->sortable);
        }

        return $columns;
    }
public function setSortableColumns ( $ columns ) { if ( ! empty ( $ this -> columns ( ) -> sortable ) ) { $ columns = array_merge ( $ columns , $ this -> columns ( ) -> sortable ) ; } return $ columns ; }
Make custom columns sortable
@param array $columns Default WordPress sortable columns
Make custom columns sortable