yii\web\UrlNormalizer::collapseSlashes PHP Метод

Collapse consecutive slashes in $pathInfo, for example converts site///index into site/index.

protected collapseSlashes ( string $pathInfo ) : string
$pathInfo	string	raw path info.
Результат	string	normalized path info.

    protected function collapseSlashes($pathInfo)
    {
        return ltrim(preg_replace('#/{2,}#', '/', $pathInfo), '/');
    }

UrlNormalizer