Cant insert hashed(bcrypt) password in mongodb using mongoose

this is my user schema

 let mongoose = require('mongoose');
mongoose.set('debug', true);

//user schema
const UserSchema = mongoose.Schema({
    name:{
        type:String,
        required:true
    },
    email:{
        type:String,
        required:true
    } ,
    username:{
        type:String,
        required:true
    },
     password:{
        type:String,
        required:true
    }
});

const User = mongoose.model('User',UserSchema);
module.exports = User;

and this is the user route file where am trying to insert a new user

if(errors){
            res.render('register',{
                errors:errors
            })
        }else{
            bcrypt.genSalt(10,(err,salt)=>{
                bcrypt.hash(password,salt,(err,hash)=>{
                    if(err){
                        console.log("hash did not work");
                    }

                        newUser.password = hash;
                        console.log(newUser.password);


                });
            })
            than()
            var newUser =  new User({
                name:name,
                email:email,
                username:username,
                password:password
            }); 


            console.log(newUser);
                newUser.save((err)=>{
                if(err){
                    console.log(err)
                    return;
                }else{
                    req.flash('success','your now registered and can login');
                    res.redirect('./login');
                }

            });
        }

i tried also assining it dirctly to the new user than save

  newUser.password = hash;

the password is getting hashed when i console log it but it doesnt store as hash value in the new user for example example from db