title: OpenID Connect - Authorization Code Flow with new Google Identity JS API
body: <p>I'm trying to understand how to implement OpenId Connect Authorization Code Flow (which is the most secure) when using newest Google Identity JS Library.
  I was able to succeed with legacy Google Sign-In JS library (as per <a href="https://developers.google.com/identity/sign-in/web/server-side-flow" rel="nofollow noreferrer">Google Sign-In for server side apps</a>), by using <code>auth2.grantOfflineAccess()</code> which was ultimately providing the required authorization <code>code</code> as per OIDC specs.
  Now with latest Google Identity library, I cannot find how to support the equivalent OIDC Authorization Code Flow. According to <a href="https://developers.google.com/identity/gsi/web/guides/migration" rel="nofollow noreferrer">Migrating from Google Sign-In</a> the <code>grantOfflineAccess()</code> JS method has been removed, but don't see how ID Token can replace the orignal authorization <code>code</code> for corresponding OIDC Authorization Code Flow. I hope I might be missing something.</p>