server-example-2.js

// on the server
import { renderToStaticMarkup } from 'react-dom/server';
import MongoClient from 'mongodb';

app.get('*', (req, res) => {
  var url = 'mongodb://localhost:27017/todo-app';
  MongoClient.connect(url, function(err, db) {
    res.status(200).render('layout', {
      locals: {
        body: renderToStaticMarkup(<TodoApp db={db}/>),
      }
    });
  });
});