class DefaultValue in GraphQL 8.4

Default value resolver.

Allows to fall back if a value is NULL.

Hierarchy

• class \Drupal\graphql\GraphQL\Resolver\DefaultValue implements ResolverInterface

1 file declares its use of DefaultValue

ResolverBuilder.php in src/GraphQL/ResolverBuilder.php

File

src/GraphQL/Resolver/DefaultValue.php, line 16

Namespace

Drupal\graphql\GraphQL\Resolver

class DefaultValue implements ResolverInterface {

  /**
   * The initial value.
   *
   * @var \Drupal\graphql\GraphQL\Resolver\ResolverInterface
   */
  protected $value;

  /**
   * The fallback value in case the initial value resolves to NULL.
   *
   * @var \Drupal\graphql\GraphQL\Resolver\ResolverInterface
   */
  protected $default;

  /**
   * DefaultValue constructor.
   *
   * @param \Drupal\graphql\GraphQL\Resolver\ResolverInterface $value
   *   The initial value to check.
   * @param \Drupal\graphql\GraphQL\Resolver\ResolverInterface $default
   *   The fallback value returned if the initial one resolves to NULL.
   */
  public function __construct(ResolverInterface $value, ResolverInterface $default) {
    $this->value = $value;
    $this->default = $default;
  }

  /**
   * {@inheritDoc}
   */
  public function resolve($value, $args, ResolveContext $context, ResolveInfo $info, FieldContext $field) {
    $result = $this->value
      ->resolve($value, $args, $context, $info, $field);
    if ($result === NULL) {
      return $this->default
        ->resolve($value, $args, $context, $info, $field);
    }
    if ($result instanceof SyncPromise) {
      return DeferredUtility::returnFinally($result, function ($current) use ($value, $args, $context, $info, $field) {
        if ($current === NULL) {
          return $this->default
            ->resolve($value, $args, $context, $info, $field);
        }
        return $current;
      });
    }
    return $result;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
DefaultValue::$default	protected	property	The fallback value in case the initial value resolves to NULL.
DefaultValue::$value	protected	property	The initial value.
DefaultValue::resolve	public	function	Resolve values for the fields. Overrides ResolverInterface::resolve
DefaultValue::__construct	public	function	DefaultValue constructor.