RelationshipNormalizer.php

<?php

namespace Drupal\jsonapi\Normalizer;

use Drupal\jsonapi\JsonApiResource\Relationship;
use Drupal\jsonapi\Normalizer\Value\CacheableNormalization;

/**
 * Normalizes a JSON:API relationship object.
 *
 * @internal
 */
class RelationshipNormalizer extends NormalizerBase {
  
  /**
   * {@inheritdoc}
   */
  protected $supportedInterfaceOrClass = Relationship::class;
  
  /**
   * {@inheritdoc}
   */
  public function normalize($object, $format = NULL, array $context = []) {
    assert($object instanceof Relationship);
    return CacheableNormalization::aggregate([
      'data' => $this->serializer
        ->normalize($object->getData(), $format, $context),
      'links' => $this->serializer
        ->normalize($object->getLinks(), $format, $context)
        ->omitIfEmpty(),
      'meta' => CacheableNormalization::permanent($object->getMeta())
        ->omitIfEmpty(),
    ]);
  }

}