I have followed the Google migration guide and successfully generated a token so that my angular code can get server responses. The server needs a token Refresh after an hour.

I can find nothing in the migration guide or related documents that give a clue about obtaining a Refresh token.

The migration guide can be found at Https://developers.google.com/identity/gsi/web/guides/migration. I have used the html JavaScript popup code sample.

There are similar questions on stackoverflow but these do not seem to cover the latest new Google identity Services SDK.