Walking a directory with Node.js

var path = dir + "/" + file;

You forgot to make path a local variable. Now it won't be changed behind your back in the loop.

Use node-dir for this. Because you need a separate action for directories and files, I'll give you 2 simple iterators using node-dir.

Asynchronously iterate the files of a directory and its subdirectories and pass an array of file paths to a callback.

var dir = require('node-dir');

dir.files(__dirname, function(err, files) {
  if (err) throw err;
  console.log(files);
  //we have an array of files now, so now we'll iterate that array
  files.forEach(function(filepath) {
    actionOnFile(null, filepath);
  })
});

Asynchronously iterate the subdirectories of a directory and its subdirectories and pass an array of directory paths to a callback.

var dir = require('node-dir');

dir.subdirs(__dirname, function(err, subdirs) {
  if (err) throw err;
  console.log(subdirs);
  //we have an array of subdirs now, so now we'll iterate that array
  subdirs.forEach(function(filepath) {
    actionOnDir(null, filepath);
  })
});