FluidTYPO3\Vhs\ViewHelpers\Menu\AbstractMenuViewHelper::determineParentPageUid PHP Method

    protected function determineParentPageUid($pageUid = null, $entryLevel = 0)
    {
        $rootLineData = $this->pageService->getRootLine();
        if (null === $pageUid) {
            if (null !== $entryLevel) {
                if ($entryLevel < 0) {
                    $entryLevel = count($rootLineData) - 1 + $entryLevel;
                }
                $pageUid = $rootLineData[$entryLevel]['uid'];
            } else {
                $pageUid = $GLOBALS['TSFE']->id;
            }
        }
        return $pageUid;
    }