EntityTree

<?php

namespace App\Services;


use App\Models\Entity;
use Illuminate\Support\Arr;
use Illuminate\Support\Collection;

class EntityTree
{
    public $array = [];

    public $temp = [];


    /**
     * @param array $elements
     * @param int $parentId
     * @return array
     */
    public function build(array $elements, $parentId = null): array
    {
        $branch = array();
        $child = array();
        foreach ($elements as $element) {
            if ($element['parent_id'] == $parentId) {
                $children = $this->build($elements, $element['id']);
                if ($children) {
                    $element['children'] = $children;
                }
                $child  = Arr::add($element, 'children', array());
                $branch[] = $child;
            }
        }

        return $branch;
    }

}