GraphQL\Type\Definition\Config::validateField PHP Method

    public static function validateField($typeName, array $config, array $definition)
    {
        if (self::$enableValidation) {
            if (!isset($config['name'])) {
                $pathStr = isset($config['type']) ? '(Unknown Field of type: ' . Utils::printSafe($config['type']) . ')' : '(Unknown Field)';
            } else {
                $pathStr = '';
            }
            self::validateMap($typeName ?: '(Unnamed Type)', $config, $definition, $pathStr);
        }
    }

 /**
  * @param array|Config $field
  * @param string $typeName
  * @return FieldDefinition
  */
 public static function create($field, $typeName = null)
 {
     if ($typeName) {
         Config::validateField($typeName, $field, self::getDefinition());
     }
     return new self($field);
 }