Sortoperation for nodes in TYPO3 Neos

SortRecursiveOperation.php

<?php
namespace Vendor\Package\TypoScript\FlowQueryOperations;

/*                                                                        *
 * This script belongs to the TYPO3 Flow package "Vendor.Package".        *
 *                                                                        *
 * It is free software; you can redistribute it and/or modify it under    *
 * the terms of the GNU Lesser General Public License, either version 3   *
 * of the License, or (at your option) any later version.                 *
 *                                                                        *
 * The TYPO3 project - inspiring people to share!                         *
 *                                                                        */

use TYPO3\Eel\FlowQuery\Operations\AbstractOperation;
use TYPO3\Flow\Annotations as Flow;
use TYPO3\TYPO3CR\Domain\Model\NodeInterface;
use TYPO3\Eel\FlowQuery\FlowQuery;

/**
 * Sort operation to sort nodes by their position in the node tree
 *
 * Use it like this:
 *
 *    ${q(node).children().sortRecursive(['ASC'|'DESC'])}
 */
class SortRecursiveOperation extends AbstractOperation {

	/**
	 * {@inheritdoc}
	 *
	 * @var string
	 */
	static protected $shortName = 'sortRecursive';

	/**
	 * {@inheritdoc}
	 *
	 * @var integer
	 */
	static protected $priority = 100;

	/**
	 * {@inheritdoc}
	 *
	 * We can only handle TYPO3CR Nodes.
	 *
	 * @param mixed $context
	 * @return boolean
	 */
	public function canEvaluate($context) {
		return (isset($context[0]) && ($context[0] instanceof NodeInterface));
	}

	/**
	 * {@inheritdoc}
	 *
	 * @param FlowQuery $flowQuery the FlowQuery object
	 * @param array $arguments the arguments for this operation
	 * @return mixed
	 */
	public function evaluate(FlowQuery $flowQuery, array $arguments) {
		$nodes = $flowQuery->getContext();

		$sortOrder = 'ASC';
		if (isset($arguments[0]) && !empty($arguments[0]) && in_array($arguments[0], array('ASC', 'DESC'))) {
			$sortOrder = $arguments[0];
		}

		$getIndexPath = function(NodeInterface $node) {
			$indexPath = array($node->getIndex());
			while ($node = $node->getParent()) {
				$indexPath[]= $node->getIndex();
			}
			return $indexPath;
		};

		$cmpIndex = function(NodeInterface $a, NodeInterface $b) use ($getIndexPath) {
			if ($a == $b) {
				return 0;
			}

			// Compare index path backwards until a difference is found
			$aIndexPath = $getIndexPath($a);
			$bIndexPath = $getIndexPath($b);
			while (count($aIndexPath) > 0 && count($bIndexPath) > 0) {
				$diff = (array_pop($aIndexPath) - array_pop($bIndexPath));
				if ($diff !== 0) {
					return $diff < 0 ? -1 : 1;
				}
			}
			return 0;
		};

		usort($nodes, $cmpIndex);
		if ($sortOrder === 'DESC') {
			$nodes = array_reverse($nodes);
		}

		$flowQuery->setContext($nodes);
	}
}