I'm trying to register an user and I use a constructor class for it, but when I put the parameters in the constructor and make the query, it takes the first parameter that I passed to the constructor and puts all the information as if it were an object of that parameter. Like this:

And when I try to put a parameter to be able to use it like this this.username = username, I meet with this

Here's my code:

class User{
    constructor(user){
        this.username = user.username
        this.email = user.email
        this.birthday = user.birthday
        this.picture = user.picture
        this.password = user.password
    }
}

//////

async signUp(req,res){
        const newUser = new User(req.body)
        console.log(newUser)
        const result = await newUser.save()
        console.log(result)
        return res.redirect("/")
}

////

router.post("/signup", authcontroller.signUp)