Services.yaml

services:
  _defaults:
    autowire: true
    autoconfigure: true
    public: false
  BasisWeb\TagContentObject\:
    resource: '../Classes/*'

  BasisWeb\TagContentObject\ContentObject\TagContentObject:
    tags:
      - name: frontend.contentobject
        identifier: 'TAG'

TagContentObject.php

<?php

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

namespace BasisWeb\TagContentObject\ContentObject;

use TYPO3\CMS\Core\Context\TypoScriptAspect;
use TYPO3\CMS\Core\TypoScript\TypoScriptService;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Extbase\Utility\DebuggerUtility;
use TYPO3\CMS\Frontend\ContentObject\AbstractContentObject;

/**
 * Contains TAG class object.
 */
class TagContentObject extends AbstractContentObject
{
    protected static $SELF_CLOSING_TAGS = ['area', 'base', 'br', 'col', 'command', 'embed', 'hr', 'img', 'input', 'keygen', 'link', 'meta', 'param', 'source', 'track', 'wbr'];

    /**
     * Rendering the cObject, TAG
     *
     * @param array $conf Array of TypoScript properties
     * @return string Output
     */
    public function render($conf = [])
    {
        if (!empty($conf['if.']) && !$this->cObj->checkIf($conf['if.'])) {
            return '';
        }

        $tagName = $conf['tagName'] ?? 'div';
        if ($conf['tagName.'] ?? false) {
            $this->cObj->cObjGetSingle($tagName, $conf['tagName.'] ?? []);
        }

        /*
        $tagName = (($conf['tagName'] ?? false) && ($conf['tagName.'] ?? false)) ?
            $this->cObj->cObjGetSingle($conf['tagName'], $conf['tagName.'] ?? []) :
            'div';
        */
        $tagAttributes = [];
        $tagContent = '';

        $omitClosingTag = $conf['omitClosingTag'] ?? false;
        $selfClosingTag = in_array($tagName, self::$SELF_CLOSING_TAGS, true) || (boolean) ($conf['selfClosingTag'] ?? false);
        $attributes = $conf['attributes.'] ?? [];

        foreach ($attributes as $attributeName => $attributeValue) {
            if (str_ends_with($attributeName, '.')) {
                continue;
            }

            $tagAttributes[htmlspecialchars((string) $attributeName, ENT_COMPAT, 'UTF-8', false)][] = htmlspecialchars(
                (string) $this->cObj->cObjGetSingle(
                    $conf['attributes.'][$attributeName],
                    $conf['attributes.'][$attributeName . '.'] ?? []
                ),
                ENT_COMPAT, 'UTF-8', false
            );
        }

        $tagContent = (($conf['content'] ?? false) && ($conf['content.'] ?? false)) ?
            $this->cObj->cObjGetSingle($conf['content'], $conf['content.'] ?? []) :
            $conf['content'] ?? '';

        return '<' . $tagName . self::renderAttributes($tagAttributes) . ($selfClosingTag ? ' /' : '') . '>' . (!$omitClosingTag && !$selfClosingTag ? $tagContent . '</' . $tagName . '>' : '');
    }



    private static function renderAttributes(array $attributes): string
    {
        $result = '';

        foreach ($attributes as $key => $values) {
            $result .= ' ' . $key . '="' . implode(' ', $values) . '"';
        }

        return rtrim($result);
    }
}