File uploads in Node.js

file-upload.js

var multiparty = require('multiparty'),
    mkdirp = require('mkdirp'),
    path = require('path'),
    fs = require('fs');

module.exports = function handleFileUpload(req, res, saveDir, cb) {
  var form = new multiparty.Form();
  mkdirp(saveDir, function(err) {
    if (err) return cb(err);
    form.parse(req, function(err, fields, files) {
      if (err) return cb(err);
      try {
        for (var key in files) {
          files[key].forEach(moveFile);
        }
      }
      catch(err) {
        return cb(err);
      }
      cb(null, fields, files);

      function(file, index) {
        var savePath = path.resolve(saveDir, file.originalFilename);
        fs.renameSync(file.path, savePath);
        files[key][index].path = savePath;
      }
    });
  });
}