outline-8.x-1.x-dev/modules/outline_graphql/src/Plugin/GraphQL/DataProducer/Entry/ReferencedEntityId.php

<?php

namespace Drupal\outline_graphql\Plugin\GraphQL\DataProducer\Entry;

use Drupal\Core\Entity\EntityInterface;
use Drupal\graphql\Plugin\GraphQL\DataProducer\DataProducerPluginBase;

/**
 * @DataProducer(
 *   id = "referenced_entity_id",
 *   name = @Translation("Referenced Entity ID"),
 *   description = @Translation("Returns the referenced entity's ID of an entry."),
 *   produces = @ContextDefinition("string",
 *     label = @Translation("Referenced Entity ID")
 *   ),
 *   consumes = {
 *     "entity" = @ContextDefinition("entity",
 *       label = @Translation("Entity")
 *     )
 *   }
 * )
 */
class ReferencedEntityId extends DataProducerPluginBase {

  /**
   * @param \Drupal\Core\Entity\EntityInterface $entity
   *
   * @return string
   */
  public function resolve(EntityInterface $entity) {
    return $entity->getReferencedEntityId();
  }

}