MarkupNormalizer.php

<?php

namespace Drupal\serialization\Normalizer;

use Drupal\Component\Render\MarkupInterface;

/**
 * Normalizes MarkupInterface objects into a string.
 */
class MarkupNormalizer extends NormalizerBase {
  
  /**
   * {@inheritdoc}
   */
  public function normalize($object, $format = NULL, array $context = []) : array|string|int|float|bool|\ArrayObject|null {
    return (string) $object;
  }
  
  /**
   * {@inheritdoc}
   */
  public function hasCacheableSupportsMethod() : bool {
    @trigger_error(__METHOD__ . '() is deprecated in drupal:10.1.0 and is removed from drupal:11.0.0. Use getSupportedTypes() instead. See https://www.drupal.org/node/3359695', E_USER_DEPRECATED);
    return TRUE;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getSupportedTypes(?string $format) : array {
    return [
      MarkupInterface::class => TRUE,
    ];
  }

}