src/Xiphe/THEWPTOOLS.php
function get_nav_menu_item_children( $parent_id, $nav_menu_items, $depth = true ) {
        $nav_menu_item_list = array();
        foreach ( (array) $nav_menu_items as $nav_menu_item ) {
            if ( $nav_menu_item->menu_item_parent == $parent_id ) {
                $nav_menu_item_list[] = $nav_menu_item;
                if ( $depth ) {
                    if ( $children = self::get_nav_menu_item_children( $nav_menu_item->ID, $nav_menu_items ) )
                        $nav_menu_item_list = array_merge( $nav_menu_item_list, $children );
                    }
                }
        }
        return $nav_menu_item_list;
    }
function get_nav_menu_item_children( $parent_id, $nav_menu_items, $depth = true ) {
        $nav_menu_item_list = array();
        foreach ( (array) $nav_menu_items as $nav_menu_item ) {
            if ( $nav_menu_item->menu_item_parent == $parent_id ) {
                $nav_menu_item_list[] = $nav_menu_item;
                if ( $depth ) {
                    if ( $children = self::get_nav_menu_item_children( $nav_menu_item->ID, $nav_menu_items ) )
                        $nav_menu_item_list = array_merge( $nav_menu_item_list, $children );
                    }
                }
        }
        return $nav_menu_item_list;
    }
function get_nav_menu_item_children ( $ parent_id , $ nav_menu_items , $ depth = true ) { $ nav_menu_item_list = array ( ) ; foreach ( ( array ) $ nav_menu_items as $ nav_menu_item ) { if ( $ nav_menu_item -> menu_item_parent == $ parent_id ) { $ nav_menu_item_list [ ] = $ nav_menu_item ; if ( $ depth ) { if ( $ children = self :: get_nav_menu_item_children ( $ nav_menu_item -> ID , $ nav_menu_items ) ) $ nav_menu_item_list = array_merge ( $ nav_menu_item_list , $ children ) ; } } } return $ nav_menu_item_list ; }
Returns all child nav_menu_items under a specific parent

http://wpsmith.net/2011/wp/how-to-get-all-the-children-of-a-specific-nav-menu-item/

@param   int       the parent nav_menu_item ID
@param   array     nav_menu_items
@param   bool      gives all children or direct children only
@return  array     returns filtered array of nav_menu_items
Returns all child nav_menu_items under a specific parent