Mongoose stopped accepting callbacks for some of its functions

I’ve been using callbacks for .save() and .findOne() for a few days now and just today I encounter these errors:

throw new MongooseError('Model.prototype.save() no longer accepts a callback')

MongooseError: Model.prototype.save() no longer accepts a callback

and

MongooseError: Model.findOne() no longer accepts a callback

It’s really awkward given that callbacks are still accepted in the docs at least for .findOne().

app.post("/register", (req, res) => {
    const newUser = new User({
        email: req.body.username,
        password: req.body.password
    });

    newUser.save((err) => {
        if (err) console.log(err)
        else res.render("secrets");
    });
});

This is what used to work for me, using express and mongoose. Please let me know how to fix it.

>Solution :

app.post("/login",function(req,res){
    const username = req.body.username;
    const password = req.body.password;

    User.findOne({email:username})
    .then((foundUser) => {
        if(foundUser){
            if(foundUser.password === password){
                res.render("secrets");
            }
        }
   })
   .catch((error) => {
       //When there are errors We handle them here

console.log(err);
       res.send(400, "Bad Request");
   });
      
});

This works for me, also im doing the web dev bootcamp by angela yu.

It seems like now you have to use => then and =>catch for the handling