PHP function to get the folder size including subfolders

foldersize.php

<?php

/**
 * Retrieve folder size including subfolders 
 * and including 'hidden' files and folders
 * 
 * @param  string $dir  Directory path
 * @return int          Size of the directory in bytes
 */
function folderSize($dir)
{
    $size = 0;
    $dir  = rtrim($dir, '/\\').DIRECTORY_SEPARATOR.'{,.}*';
    $list = glob($dir, GLOB_BRACE);
    $list = array_filter($list, function($v){
        return preg_match('%(\\\\|/)\.{1,2}$%im', $v) ? false : true;
    });

    foreach ($list as $each) {
        $size += is_file($each) ? filesize($each) : folderSize($each);
    }

    return $size;
}