src/Config/Config.php
protected function getGroupName(/*# string */ $id)/*# : string */
    {
        return explode(
            $this->config->getDelimiter(),
            ltrim($id, $this->config->getDelimiter())
        )[0];
    }
protected function getGroupName(/*# string */ $id)/*# : string */
    {
        return explode(
            $this->config->getDelimiter(),
            ltrim($id, $this->config->getDelimiter())
        )[0];
    }
protected function getGroupName ( /*# string */ $ id ) /*# : string */ { return explode ( $ this -> config -> getDelimiter ( ) , ltrim ( $ id , $ this -> config -> getDelimiter ( ) ) ) [ 0 ] ; }
Get group name

- returns 'system' from $id 'system.dir.tmp'
- '.system.tmpdir' is invalid

@param  string $id
@return string
@access protected
Get group name