eZ\Publish\Core\Repository\Helper\FieldTypeRegistry::hasFieldType PHP Method

    public function hasFieldType($identifier)
    {
        return isset($this->fieldTypes[$identifier]);
    }

 /**
  * Returns if there is a FieldType registered under $identifier
  *
  * @param string $identifier
  *
  * @return boolean
  */
 public function hasFieldType($identifier)
 {
     return $this->fieldTypeRegistry->hasFieldType($identifier);
 }