Use EelExpressions to filter Nodes in PHP

EelExpressions to filter Nodes in PHP

/**
 * @var SiteRepository
 * @Flow\Inject
 */
protected $siteRepository;

/**
 * @var \TYPO3\Neos\Domain\Service\ContentContextFactory
 * @Flow\Inject
 */
protected $contentContextFactory;

/**    ---------------------------------------- */

/** @var \TYPO3\Neos\Domain\Model\Site $site */
$site = $this->siteRepository->findOnline()->getFirst();

/** @var ContentContext $context */
$context = $this->contentContextFactory->create(array("currentSite" => $site));

/* Will be an instance of \TYPO3\Eel\CompilingEvaluator */
$eelEvauator = $this->objectManager->get('TYPO3\Eel\EelEvaluatorInterface');

/** 
 * Don't forget to provide an array with all context variables like "site" in
 * this example
 *
 * @var \TYPO3\Eel\FlowQuery\FlowQuery $nodes 
 */
$nodeCount = \TYPO3\Eel\Utility::evaluateEelExpression('${q(site).children("main").count()}', $eelEvauator, array("site" => $context->getCurrentSiteNode()));