gistfile1.txt

<?php

namespace Drupal\bullseye_api\Normalizer;

use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
use Drupal\Core\Datetime\DrupalDateTime;
use Drupal\node\Entity\Node;

/**
* Custom Normalization for Benefit entities.
*/
class BenefitDenormalizer extends DenormalizerInterface {

  protected $supportedInterfaceOrClass = 'Drupal\Core\TypedData\TypedDataInterface';

  public function supportsDenormalization($data, $class, $format = null, array $context = array()) {
    // If we aren't dealing with an object or the format is not supported return now.
    if (!is_array($data) || !$this->checkFormat($format)) {
      return FALSE;
    }
    // This custom normalizer should be supported for Article bundle for the Node Entity.
    if ( $class instanceOf Node ) {
      return $this->hasRequiredFields($data); // You could perform a check to make sure we are getting what we expect..
    }

    // Otherwise, this normalizer does not support the $data object.
    return FALSE;
  }

  /**
  * {@inheritdoc}
  */
  public function denormalize($data, $class, $format = null, array $context = array()) {
    $data = [];
    $entity = FALSE;
    if ($data['id']) {
     // Load and update the entity, return it.
     $entity = entity_load('node', $data['id']);
     ....
    }
    else {
     // Create a new entity.
     $data =  [
      'id' => $entity->id(),
      'type' => $entity->bundle(),
      'title' => $entity->title->value,
      'summary' => $entity->body->summary,
      ...
    ];
    $entity = Node::create($data);
    }
    return $entity;
  }
}