#php Recursive function that creates a parent children nested array of unlimited hierarchy

tree.php

<?php 

/**
 * @param $elements format like following
 *      [
            'id' => 1,
            'name' => 'root1',
            'parent_id' => 0
        ]
 */
function buildTree(array $elements, $parentId = 0) {
    $branch = array();

    foreach ($elements as $element) {
        if ($element['parent_id'] == $parentId) {
            $children = buildTree($elements, $element['id']);
            if ($children) {
                $element['children'] = $children;
            }
            $branch[] = $element;
        }
    }

    return $branch;
}