formidable handle no uploaded file errors

Question

Everything is working as expected in my code except if the user has not uploaded a file it crashes my node app.

The error is arising at the fs.rename part, as there is nothing uploaded the app cant rename anything and causes the following:

Error:

EPERM: operation not permitted, rename 'C:\Users\xxx\AppData\Local\Temp\upload_0a145049089fa69e9df64f8d20abb362' -> 'C:\Users\xxx\Dropbox\Automate NodeJS\Login_Register+Submit - 0.01\data\5be13231807fe33f14b2834a\sdS9m'

Im having difficulty searching for my err and how to handle that, If anyone can point me to some resources for how to handle formidable errors and how to stop the process of the user hasn't uploaded anything it would be fantastic.

It's not a production app or anything of the like its just me learning how to deal with multiple functions and a database at once.

router.post('/submit', userisSubbed, userhasTime, (req, res, next0) => {
var userId = req.user._id;
var username = req.user.email;
var isCompleted = 'No'
var jobNumber = generator.generate({
    length: 5,
    numbers: true
});
// Validate
const errors = req.validationErrors();

if (errors) {
    res.render('index', {
        errors: errors
    });}    

    else {
        var form = new formidable.IncomingForm();
        form.parse(req, function (err, fields, files) {
        var userPath = req.user._id
        var dir = './data/' + userPath + '/' + jobNumber + '/';
        if (!fs.existsSync(dir)){
            fs.mkdirSync(dir);

          }else
          {
              console.log("Directory already exist");
        }

        var oldpath = files.filetoupload.path;
        var newpath = dir + files.filetoupload.name;
        // copy the file to a new location
        fs.rename(oldpath, newpath, function (err) {
            if (err) throw err;
            console.log('renamed complete');
        const newJob = new Job({
            userId: userId,
            username: username,
            isCompleted: isCompleted,
            filepath: newpath,
            jobNumber: jobNumber,
        });
        Job.createJob(newJob, function(err, job){
            if (err) throw err;
            console.log(job);
        });
    req.flash('success_msg', 'Job Submitted...');
    res.redirect('/')
     });
  });
 }
});