private function getOrderingDescendants($depth = null, $order = [])
    {
        if (1 === $depth && true === empty($order)) {
            $order = [
                '_position' => 'ASC',
                '_leftnode' => 'ASC',
            ];
        } elseif (true === empty($order)) {
            $order = [
                '_leftnode' => 'ASC',
                '_level' => 'ASC',
                '_position' => 'ASC',
            ];
        }

        return $order;
    }
private function getOrderingDescendants($depth = null, $order = [])
    {
        if (1 === $depth && true === empty($order)) {
            $order = [
                '_position' => 'ASC',
                '_leftnode' => 'ASC',
            ];
        } elseif (true === empty($order)) {
            $order = [
                '_leftnode' => 'ASC',
                '_level' => 'ASC',
                '_position' => 'ASC',
            ];
        }

        return $order;
    }
private function getOrderingDescendants ( $ depth = null , $ order = [ ] ) { if ( 1 === $ depth && true === empty ( $ order ) ) { $ order = [ '_position' => 'ASC' , '_leftnode' => 'ASC' , ] ; } elseif ( true === empty ( $ order ) ) { $ order = [ '_leftnode' => 'ASC' , '_level' => 'ASC' , '_position' => 'ASC' , ] ; } return $ order ; }
Returns default ordering criteria for descendants if none provided.

@param  integer|null         $depth              Optional, limit to $depth number of generation.
@param  array                $order              Optional, the ordering criteria ( [] by default ).

@return array                                    If none ordering criteria provided and only one descendant generation is requested
the result will be array['_position' => 'ASC', '_leftnode' => 'ASC']
If none ordering criteria provided and several generations requested the result
will be array['_leftnode' => 'ASC', '_level' => 'ASC', '_position' => 'ASC']
elsewhere $order.
Returns default ordering criteria for descendants if none provided .