(Firebase,js) Problem with creating document that have userID as documentID

So i’m working on registration system using firebase authentication and this is what i want to achieve is:

1. user registers with name,surname,email and password(for that im using createUserWithEmailAndPassword())
2. once user registered, system creates document in collection “users”, that documentID matches registered userID.
   3.That newly created document create fields: name and surname based on user input.

I’m currently stuck at the moment of creating document and i don’t know how to make it work properly.

Finally i ended up with this:

signupForm.addEventListener("submit",(e)=>{
  e.preventDefault();
  const name = signupForm.name.value;
  const surname = signupForm.surname.value;
  const email = signupForm.email.value;
  const password = signupForm.password.value;
  
  createUserWithEmailAndPassword(auth, email, password)
    .then(cred => {
      signupForm.reset();
      userId = cred.user.uid;
      
    })
    .catch(err => {
      console.log(err.message);
    });
  
  setUserData(userId,name,surname);
});

function setUserData(userId,name,surname){
  const userRef = doc(db,"users",userId);
  setDoc(userRef,{
    name: name,
    surname: surname
  }).then(() => {
    console.log("Document successfully written!");
  })
  .catch((error) => {
    console.error("Error writing document: ", error);
  });
}

it throws: Uncaught FirebaseError: Invalid document reference. Document references must have an even number of segments, but users has 1.

I tried many solutions from stackoverflow and even chatGPT, nothing works. How can i fix this?