Method getExtensionNameFromAsset

/**
 * Method to get the extension name from the asset name.
 *
 * @param   integer|string  $assetKey  The asset key (asset id or asset name).
 *
 * @return  string  The extension name (ex: com_content).
 *
 * @since    1.6
 */
public static function getExtensionNameFromAsset($assetKey)
{
    static $loaded = array();
    if (!isset($loaded[$assetKey])) {
        $assetName = self::getAssetName($assetKey);
        $firstDot = strpos($assetName, '.');
        if ($assetName !== 'root.1' && $firstDot !== false) {
            $assetName = substr($assetName, 0, $firstDot);
        }
        $loaded[$assetKey] = $assetName;
    }
    return $loaded[$assetKey];
}