server.js

server.use((req, res)=> {
  match({
    'routes': routes,
    'location': req.url
  }, (error, redirectLocation, renderProps) => {
    if (error) {
      res.status(500).send(error.message);
    } else if (redirectLocation) {
      res.redirect(302, redirectLocation.pathname + redirectLocation.search);
    } else if (renderProps) {

      // Create a new Redux store instance
      const store = configureStore();

      // Render the component to a string
      const html = renderToString(
        <Provider store={store}>
          <RouterContext {...renderProps} />
        </Provider>
      );

      const preloadedState = store.getState();

      fs.readFile('./dist/index.html', 'utf8', function (err, file) {
        if (err) {
          return console.log(err);
        }
        let document = file.replace(/<div id="app"><\/div>/, `<div id="app">${html}</div>`);
        document = document.replace(/'preloadedState'/, `'${JSON.stringify(preloadedState)}'`);
        res.setHeader('Cache-Control', 'public, max-age=31536000');
        res.setHeader("Expires", new Date(Date.now() + 2592000000).toUTCString());
        res.send(document);
      });

    } else {
      res.status(404).send('Not found')
    }
  });
});