TYPO3 Form Framework: Use hook to prefill hidden form field with current page title and UID

ext_localconf.php

<?php

use Sebkln\FormExamples\Hooks\PrefillFormWithCurrentPageHook;

defined('TYPO3') or die();

(static function () {
    $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['ext/form']['beforeRendering'][1679897346] = PrefillFormWithCurrentPageHook::class;
})();

PrefillFormWithCurrentPageHook.php

<?php

namespace Sebkln\FormExamples\Hooks;

use TYPO3\CMS\Form\Domain\Model\Renderable\RootRenderableInterface;
use TYPO3\CMS\Form\Domain\Runtime\FormRuntime;

class PrefillFormWithCurrentPageHook {
    /**
     * @param FormRuntime $formRuntime
     * @param RootRenderableInterface $renderable
     * @return void
     *
     * Usage in form definition:
     *  -
     *    defaultValue: ''
     *    type: Hidden
     *    identifier: pageInfo
     *    label: 'Current page'
     *    variants:
     *    -
     *    identifier: hide-pageInfo
     *    renderingOptions:
     *    enabled: false
     *    condition: 'stepType == "SummaryPage" || finisherIdentifier in ["EmailToSender"]'
     */
    public function beforeRendering(FormRuntime $formRuntime, RootRenderableInterface $renderable): void
    {
        if ($renderable->getIdentifier() === 'pageInfo') {
            $pageTitle = $GLOBALS['TSFE']->page['title'];
            $pageId = $GLOBALS['TSFE']->id;
            $renderable->setDefaultValue($pageTitle . ' (ID: ' . $pageId . ')');
        }
    }
}