const userRegistrationPost = (req, res) => {
const{name, email, pass1, pass2} = req.body;

    let errors = [];

    if(!name|| !email || !pass1 || !pass2){
        errors.push({msg: "Please ensure all fields are filled"});
    }

    if(pass1 !==pass2){
        errors.push({msg: "Passwords don't match"});
    }
    
    if(pass1.length < 6){   //line 66
        errors.push({msg: "Passwords must be at least 6 characters"});
    }

    if(errors.length > 0){
        res.render("user_registration", {errors, name, email, pass1, pass2})
    }else{
    //WE DON'T WANT TO HAVE 2 USERS WITH THE SAME EMAIL
        User.findOne({email: email})
        .then((result)=> {
            if(result){
                errors.push({msg: "Email already exists"});
                res.render("user_registration", errors, name, email, pass1, pass2)
            }else{
                //HERE WE TRY TO ENCRYPT OUR PASSWORD
                bcrypt.hash(pass1, 10, (error, hash)=>{
                    const nUser = new User({
                        name, email, password: hash,
                    })
                    try{
                        nUser.save();
                        req.flash('message', "Registration Successful. You can now Signup")
                        res.redirect('/user_login');
                    }
                    catch(err){
                        req.flash('error_msg', "Could not save into the Database");
                        res.redirect('user_registration');
                    }
                })
            }
        })
        .catch((err)=> {
            res.send("There's a problem");
            console.log(err);
        })
    }

}

It says the error occurs on line 66. It was supposed to save users into the database after inputing their details but it keeps giving me TypeError.