How to refresh expired google sign-in logins?

Question

I\'m using Google Sign-In. A user comes to my site and logs in with gapi.auth2.getAuthInstance().signIn(), or they are already logged in and when the page loads

Answer 1

I've raised an issue with Google over this because it's simply ridiculous they haven't documented this properly.

My comment here advises how I've accomplished refresh using the above.