Firebase Authentication detect if user came from redirect login

Question

When using Firebase Authentication's firebase.auth().getRedirectResult() method, is there a way to detect if we should expect a result (or if the user came from a redirect login)?

There's a delay in when this method is run and when a success/error callback occurs. I'd like to show some loading state as soon as possible and don't see any methods in the documentation, like isRedirectResult .

---

For example, I'd like something like this (psuedo-code)

button.onclick = () => {
  firebase.auth().signInWithRedirect(provider);
}
if (isFromRedirectPage) { // how do i do this??
  button.loading = true;
  await firebase.auth().getRedirectResult();
  button.loading = false;
} else {
  button.show();
}

Answer 1

Could be confusion around what the method was called, but I was able to use firebase.auth().onAuthStateChanged((user) => {...}) to solve this after all.

This method calls the callback function even if the user is not logged in, so I use that to determine loading state:

loading = true;
firebase.auth().onAuthStateChanged((user) => {
  loading = false;
  if (!user) {
     // show login button
  } else {
     // hide login button
  }
});