Flutter How to check whether the user sign up with google provider before?
Solution 1:
You can use the pre-built method "isNewUser" of the "UserCredential" class. Call the sing in with credentials function from a variable and use said variable to perform the check.
...
var result =
await FirebaseAuth.instance.signInWithCredential(credential);
if (result.additionalUserInfo!.isNewUser) {
// Perform what you need to do for new users here
// like creating a user document
}else {
//Perform what you want to do for old users here
//like fetching a specific user document
}
...