Extended FlowQuery FilterOperation with array support (reference and references)

FilterOperation.php

<?php
namespace MyProject\Neos\Blog\Eel\FlowQueryOperations;

use TYPO3\TYPO3CR\Domain\Model\NodeInterface;

/**
 * Override the default FilterOperation to support filtering of NodeInterface values
 * (reference) by identifier (with "=") or references by containing a value ("*=")
 */
class FilterOperation extends \TYPO3\TYPO3CR\Eel\FlowQueryOperations\FilterOperation
{

    /**
     * {@inheritdoc}
     *
     * @var integer
     */
    protected static $priority = 200;

    /**
     * {@inheritdoc}
     *
     * @param mixed $value
     * @param string $operator
     * @param mixed $operand
     * @return boolean
     */
    protected function evaluateOperator($value, $operator, $operand)
    {
        if ($value instanceof NodeInterface && ($operator === '=' || $operator === '!=')) {
            $value = $value->getIdentifier();
        } elseif (is_array($value) && $operator === '*=') {
            foreach ($value as $item) {
                if ($this->evaluateOperator($item, '=', $operand)) {
                    return true;
                }
            }
            return false;
        }
        return parent::evaluateOperator($value, $operator, $operand);
    }
}