I have migrated recently to firebase JS SDK v9 (in compat mode) and the first time the user auth token is refreshed the auth.onAuthStateChanged listener is called.
Is anybody experienced the same issue?
Docs are clear After 4.0.0, the observer is only triggered on sign-in or sign-out.
The next code reproduces the issue:
<html>
<script src="https://www.gstatic.com/firebasejs/9.1.3/firebase-app-compat.js"></script>
<script src="https://www.gstatic.com/firebasejs/9.1.3/firebase-auth-compat.js"></script>
<script>
// Initialize Firebase
const config = {
apiKey: '',
authDomain: '',
databaseURL: '',
projectId: '',
storageBucket: '',
messagingSenderId: '',
appId: '',
};
const email = "mail12345@mail.com";
const pass = "123456abc";
const app = firebase.initializeApp(config);
const auth = app.auth();
const example = async () => {
auth.onAuthStateChanged(async (user) => {
console.log('onAuthStateChanged user uid', user ? user.uid : 'null');
if (!user) {
try {
await auth.createUserWithEmailAndPassword(email, pass);
} catch (e) {
console.log('user already created');
}
console.log('signin')
await auth.signInWithEmailAndPassword(email, pass);
}
})
setInterval(() => {
console.log('force token renewal');
auth.currentUser.getIdToken(true);
}, 5000)
};
example();
</script>
</html>
If you run for the first time or if there is no session you get the output:
onAuthStateChanged user uid null <-- becuase there is no session stored
user already created
signin
onAuthStateChanged user uid mqLHdtQhwJPaXqIEbDqFBwFoxLz1 <-- this is because the signin
force token renewal <-- run each 5 secs
Having a session stored if you refresh the page you find the next output:
onAuthStateChanged user uid mqLHdtQhwJPaXqIEbDqFBwFoxLz1 <-- recover the session
force token renewal
onAuthStateChanged user uid mqLHdtQhwJPaXqIEbDqFBwFoxLz1 <-- run again after refresh token
force token renewal <-- subsequent refresh token doesn not cause a call to onAuthStateChange
The problem is with the first refresh of token. After debugging a bit in chrome I found that on the first token refresh the funcion notifyAuthListeners() from the file auth_impl.ts is invoked but the variable this.lastNotifiedUid is undefined which causes the refresh to be notified also to onAuthStateChange listeners.
Finally the issue was reported as a bug at firebase-js-sdk project (https://github.com/firebase/firebase-js-sdk/issues/5685) and fixed in record time.