how to check if user already exists or signed up already

I'm working on a user signup flow in FlutterFlow and want to ensure emails are unique. I'd like to check if an entered email address already exists in my backend before creating a new user.
Users enter their email and password during signup.

I want to check if the email already exists in my database.
- If it exists, I want to navigate them to a different page informing them about the duplicate email.
- If the email doesn't exist, I want to proceed with creating the new user and navigate them to the onboarding page.

//i have written custom action Future<bool> newCustomAction(String? email) async { // QUERY firebase COLLECTION called users if email exist return true final QuerySnapshot<Map<String, dynamic>> result = await FirebaseFirestore .instance .collection('users') .where('email', isEqualTo: email) .get(); debugPrint(email); bool isemail = result.docs.contains(email); debugPrint(isemail as String?); return result.docs.isNotEmpty; }