Give me some hints about refactoring authentication from react-router v3 => v4

help
1

I’d like to update an authorization in meteor app using react- router v4 instead of v3.

const unauthenticatedPages = ['/', '/signup'];
const authenticatedPages = ['/links'];
const onEnterPublicPage = () => {
  if (Meteor.userId()) {
    browserHistory.replace('/links');
  }
};
const onEnterPrivatePage = () => {
  if (!Meteor.userId()) {
    browserHistory.replace('/');
  }
}
const routes = (
  <Router history={browserHistory}>
    <Route path="/" component={Login} onEnter={onEnterPublicPage}/>
    <Route path="/signup" component={Signup} onEnter={onEnterPublicPage}/>
    <Route path="/links" component={Link} onEnter={onEnterPrivatePage}/>
    <Route path="*" component={NotFound}/>
  </Router>
);

Tracker.autorun(() => {
  const isAuthenticated = !!Meteor.userId();
  const pathname = browserHistory.getCurrentLocation().pathname;
  const isUnauthenticatedPage = unauthenticatedPages.includes(pathname);
  const isAuthenticatedPage = authenticatedPages.includes(pathname);

  if (isUnauthenticatedPage && isAuthenticated) {
    browserHistory.replace('/links');
  } else if (isAuthenticatedPage && !isAuthenticated) {
    browserHistory.replace('/');
  }
});

I’ve seen example from official react-router documentation page (https://reacttraining.com/react-router/web/example/auth-workflow). But still not sure how to do it.