Create a custom FlowQuery

\Vendor\Package\FlowQuery\CustomOperation

<?php

namespace Vendor\Package\FlowQuery;

class ResourceUrlOperation extends \TYPO3\Eel\FlowQuery\Operations\AbstractOperation {

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

	/**
	 * {@inheritdoc}
	 *
	 * @var boolean
	 */
	static protected $final = TRUE;

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

	/**
	 * @Flow\Inject
	 * @var ResourcePublisher
	 */
	protected $resourcePublisher;

	/**
	 * Explodes a comma-separated string with tags and fetches all assets that are tagged with those tags
	 *
	 * @param \TYPO3\Eel\FlowQuery\FlowQuery $flowQuery the FlowQuery object
	 * @param array $arguments the arguments for this operation
	 * @return mixed|null if the operation is final, the return value
	 */
	public function evaluate(\TYPO3\Eel\FlowQuery\FlowQuery $flowQuery, array $arguments){
		// do something 

		return '';
	}
}

root.ts2

result = ${q(node).custom()}