graphql_compose-1.0.0-beta20/src/Plugin/GraphQL/DataProducer/FieldProducerTrait.php

<?php

declare(strict_types=1);

namespace Drupal\graphql_compose\Plugin\GraphQL\DataProducer;

use Drupal\graphql\GraphQL\Resolver\Composite;
use Drupal\graphql\GraphQL\ResolverBuilder;

/**
 * Generic trait for fetching a property value from a field.
 */
trait FieldProducerTrait {

  /**
   * Retrieves the producers for a field.
   *
   * This is the default behavior for all field types.
   * if replacing this method, make sure to include the field_type_results
   * producer last to invoke late processing hooks.
   *
   * @param \Drupal\graphql\GraphQL\ResolverBuilder $builder
   *   The resolver builder.
   *
   * @return \Drupal\graphql\GraphQL\Resolver\Composite
   *   The composite resolver.
   */
  public function getProducers(ResolverBuilder $builder): Composite {

    return $builder->compose(
      $builder->produce('field')
        ->map('entity', $builder->fromParent())
        ->map('field', $builder->fromValue($this->getFieldName())),

      // Useful for extending this producer.
      $builder->context('field_value', $builder->fromParent()),

      // Get the field items.
      $builder->produce('field_producer_plugin')
        ->map('plugin', $builder->fromValue($this))
        ->map('value', $builder->fromParent()),
    );
  }

}