areResourceIdentifiersUnique example

// Make sure that the provided type is compatible with the targeted       // resource.       if (!in_array($value['type'], $target_resource_type_names)) {
        throw new BadRequestHttpException(sprintf(
          'The provided type (%s) does not match the destination resource types (%s).',
          $value['type'],
          implode(', ', $target_resource_type_names)
        ));
      }
      return new ResourceIdentifier($value['type'], $value['id'], $value['meta'] ?? []);
    }, $data['data']);
    if (!ResourceIdentifier::areResourceIdentifiersUnique($resource_identifiers)) {
      throw new BadRequestHttpException('Duplicate relationships are not permitted. Use `meta.arity` to distinguish resource identifiers with matching `type` and `id` values.');
    }
    return $resource_identifiers;
  }

  /** * Validates and massages the relationship input depending on the cardinality. * * @param array $data * The input data from the body. * @param bool $is_multiple * Indicates if the relationship is to-many. * * @return array * The massaged data array. */