React-Router - Uncaught TypeError: Cannot read property 'getCurrentLocation' of undefined
You are not passing a history to your <Router>.
Check out the histories documentation for more information.
Had the same error, solved it this way:
Add
var hashHistory = ReactRouter.hashHistory;
And in the Router set the history equals to hashHistory
<Router history={hashHistory}>
So in your case:
var routes = (
<Router history={hashHistory}>
<Route path="/" component={App}>
<Route path="authors" component={AuthorPage}/>
</Route>
</Router>
);