var authorisationRequestData =
  {
    'client_id': clientId,
    'scope': scopes,
    'immediate': immediate,
    prompt: 'consent',
    access_type: 'offline',
  include_granted_scope: true,
  }

  const authInstance = gapi.auth2.getAuthInstance();
  authInstance.grantOfflineAccess(authorisationRequestData)
    .then((res) => {
      console.log(gapi.auth.getToken());
      var all_token = JSON.stringify(gapi.auth.getToken());
      console.log("Token =" + all_token);
      console.log(res);
      console.log(res.code);

    }).catch(error => {
      console.log(error);
    });