code: function goBack() {
          if (History.length > 1 || location === RefreshLocation) {
            location.pop();
            return true;
          }
  
          warning(false, 'goBack() was ignored because there is no router history');
  
          return false;
        }
docs: Transitions to the previous URL if one is available. Returns true if the
  router was able to go back, false otherwise.
  
  Note: The router only tracks history entries in your application, not the
  current browser session, so you can safely call this function without guarding
  against sending the user back to some other site. However, when using
  RefreshLocation (which is the fallback for HistoryLocation in browsers that
  don't support HTML5 history) this method will *always* send the client back
  because we cannot reliably track history length.