Tree

tree.php

<?php 
namespace App\Model\Common;
class Tree {

	//building tree
	public function buildTree(array $elements, $parentId = 0) {
		$branch = array();
		$child = array();

		foreach ($elements as $element) {
			if ($element['parent_id'] == $parentId) {
				$children = $this->buildTree($elements, $element['id']);
				if ($children) {
					$element['items'] = $children;
				}
				$child  = array_add($element, 'items', array());
				$branch[] = $child;
			}
		}

		return $branch;
	}

}

?>