FilterHtmlEscape.php

<?php

namespace Drupal\filter\Plugin\Filter;

use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\filter\Attribute\Filter;
use Drupal\filter\FilterProcessResult;
use Drupal\filter\Plugin\FilterBase;
use Drupal\filter\Plugin\FilterInterface;

/**
 * Provides a filter to display any HTML as plain text.
 */
class FilterHtmlEscape extends FilterBase {
    
    /**
     * {@inheritdoc}
     */
    public function process($text, $langcode) {
        return new FilterProcessResult(_filter_html_escape($text));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getHTMLRestrictions() {
        // Nothing is allowed.
        return [
            'allowed' => [],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function tips($long = FALSE) {
        return $this->t('No HTML tags allowed.');
    }

}