PHP 無限層分類，包裹 HTML ul li 的架構 multi-level category recursion

php multi-level category recursion

/**
 * get_childs function
 * 無限層分類，包裹 HTML ul li 的架構
 *
 * @param array $items
 * @param int   $parent_id
 * @return string
 * 
 * @author VECTOR Ann <[email protected]>
 * @link https://vector.cool
 */
function get_childs( array $items = array(), int $parent_id = 0 ):string
{
    $wrap = "<ul><li><h3>%s</h3>%s</li></ul>";
    $tree = '';
    foreach ($items as $item) {
        if ($item['parent'] === $parent_id) {
            $child_tree = get_childs( $items , $item['id'] );
            $tree .= sprintf( $wrap , $item['title'] , $child_tree);
        }
    }
    return $tree;
}
echo get_childs($v_tree_demo);