how to update doc instances in mongoose code example

Example 1: mongoose find and update prop

var query = {'username': req.user.username};
req.newData.username = req.user.username;

MyModel.findOneAndUpdate(query, req.newData, {upsert: true}, function(err, doc) {
    if (err) return res.send(500, {error: err});
    return res.send('Succesfully saved.');
});

Example 2: mongoose save or update

// This will create another document if it doesn't exist
findByIdAndUpdate(_id, { something: 'updated' }, { upsert: true });