// Updating the user

auth.updateUser replaces the user and keeps the session. When you already have the new user, such as from a form's response, pass it directly: auth.updateUser(user).

When the new user comes from a request, pass a function that fetches it instead. The client notes the session before the function runs. If the session changes meanwhile, updateUser rejects with SESSION_CHANGED, and the user it fetched never lands on another account. fetchProfile is the request from Getting started:

import { fetchProfile } from "./api.js";
import { auth } from "./auth.js";

export const reloadProfile = () => auth.updateUser(fetchProfile);