code: function getExpiryDate(store, data) {
          
          var offset;
  
          if (data.cookie.originalMaxAge) {
              offset = data.cookie.originalMaxAge;
          } else {
              offset = store.sessionTimeOut * 60000;
          }
          
          return offset ? new Date(Date.now() + offset) : null;
      }
docs: expiry date for sessions