node. js gets the sum of all the file sizes in the directory

/**
* Gets the sum of all the file sizes in the specified directory in bytes
* @param dir
* @param callback
*/
function Getdirsize (dir,callback) {
var size = 0;
Fs.stat (Dir,function (err,stats) {
if (ERR) return callback (ERR);//If an error occurs
if (Stats.isfile ()) return callback (null,stats.size);//If the file

Fs.readdir (Dir,function (err,files) {//If it is a directory
if (ERR) return callback (ERR);//If traversing directory error
if (files.length==0) return callback (null,0);//If the directory is empty

var count = files.length;//Sentinel variable
for (var i = 0;i<files.length;i++) {
Getdirsize (Path.join (dir,files[i]), function (err,_size) {
if (ERR) return callback (ERR);
Size+=_size;
if (--count<=0) {//If all files (or directories) in the directory are traversed complete
Callback (Null,size);
}
});
}
});
});
}

var walk = function (dir, done) {
var results = [];
var size = 0;
Fs.readdir (dir, function (err, list) {
if (err) return done (ERR);
var pending = List.length;
if (!pending) return done (null, size);
List.foreach (function (file) {
File = Path.resolve (dir, file);
Fs.stat (file, function (err, stat) {
if (stat && stat.isdirectory ()) {
Walk (file, function (err, res) {
size = Size+res;
if (!--pending) Done (null, size);
});
} else {
size = Size+stat.size;
if (!--pending) Done (null, size);
}
});
});
});
};

node. js gets the sum of all the file sizes in the directory