Think how you would do that with session cookies - you either issue a fresh cookie or ask for login/password. Same with JWT - your client-server API wrapper can

Think how you would do that with session cookies - you either issue a fresh cookie or ask for login/password. Same with JWT - your client-server API wrapper can add a renewed token to a response when needed. There are many other reasons to have central API wrapper on the client (common error checking, serialisation, headers etc) so it doesn't cost much to stick an extra check for a new token