Is there any way to get to know the a user is already logged in any other devices ?.
In Firebase Auth service.
Anyone please let me know is there any predefined provision in Firebase Auth.
1 Answers
UserMetaData has the last sign in time. You can also set auth state persistence to be either local, session, or none.
You could use these to approximate whether a given user could be authenticated elsewhere, but it doesn't seem like there's data on whether a user is definitely currently authenticated somewhere. For that you'd need to store login/logout data separately, such as in a a Firestore document for each user.
Note that the auth service doesn't typically know (or care) whether the user is actively using the app... it just issues each user an authentication token, which is used over some period of time to prove that they are who they say the are. The token can be invalidated/refreshed from time to time for security reasons (according to the persistence setting), but it's not an indication of whether they're "active". You don't mention your use case, but if you're trying to figure out whether users are on or offline (say for a chat application), you should look at Firebase's offline capabilities.
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