Server-side rendering (SSR) in React can be difficult to wrap your head around. You're rendering on the server, then rendering on the client too? Since the SSR pattern has become more prevalent, the React team has made it easier to work with in React 16. In addition, there are a number of internal performance gains as well as efficiency gains by enabling streaming rendered content to the client.

If you want to read more about SSR in React 16, I recommend the following resources:

• https://hackernoon.com/whats-new-with-server-side-rendering-in-react-16-9b0d78585d67
• https://reactjs.org/docs/react-dom-server.html