ext_tables.php

<?php

/*
 * This file is part of the "headless" Extension for TYPO3 CMS.
 *
 * For the full copyright and license information, please read the
 * LICENSE.md file that was distributed with this source code.
 */

use FriendsOfTYPO3\Headless\Hooks\PreviewUrlHook;
use TYPO3\CMS\Core\Configuration\Features;
use TYPO3\CMS\Core\Utility\GeneralUtility;

defined('TYPO3') || die();

call_user_func(
    static function () {
        $features = GeneralUtility::makeInstance(Features::class);

        if ($features->isFeatureEnabled('headless.frontendUrls')) {
            $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_befunc.php']['viewOnClickClass'][] = PreviewUrlHook::class;
        }
    }
);