google auth.onstatechange - Javascript

The onstatechange event is triggered when there is a change in the authorization status of the user. It is triggered when the user has signed in, signed out or the authorization token has expired.

This event can be used to update the UI or perform other actions when the user's authorization status changes.

Syntax

authInstance.onstatechange = function(state) {
  // Handle the state change
};

Where:

• authInstance is the gapi.auth2 instance.
• state is an object containing the new authorization status.

Example

// Get the auth instance
var authInstance = gapi.auth2.getAuthInstance();

// Listen for state changes
authInstance.isSignedIn.listen(function(isSignedIn) {
  console.log('Signed in:', isSignedIn);
});

authInstance.currentUser.listen(function(user) {
  console.log('User changed:', user);
});

authInstance.onstatechange = function(state) {
  console.log('State changed:', state);
};

In this example, we listen for changes in the user's sign-in status and when the user changes. We also handle the state change event and log the new state to the console.

Conclusion

The onstatechange event can be used to update the UI or perform other actions when the user's authorization status changes. It is an essential feature of the gapi.auth2 API and should be used whenever the app needs to handle authorization state changes.