Smile\ElasticsuiteCore\Index\Mapping\Field::getNestedFieldName PHP Method

    public function getNestedFieldName()
    {
        $nestedFieldName = null;
        if ($this->isNested()) {
            $nestedPrefix = $this->getNestedPath() . '.';
            $nestedFieldName = str_replace($nestedPrefix, '', $this->getName());
        }
        return $nestedFieldName;
    }