How to limit property returned after save?

I'm trying to return the saved object as the request response, but I don't want whole object returned by Model.save() function, it's returning more information than I want, like _id, __v.

My request code is like this:

function insertUser(req, res) {
   const userName = req.Body.name;

      User.save({ name : userName })
         .then(r => {  
            res.send(r);
         });
}

It's returning fallowing JSON to me:

{
    _id: 590f529976aa6142d91870b7,
    name: 'blablabla'
    __v: 4
}

How can I set it to return only { name : 'blablabla' }?

via Lai32290