For about a year now I’m developing Web Applications based on React.js, and it was amazing for me to write code that actually scales with JSX components, rather than functions, it’s giving more simplicity to frontend.
But in some cases we need SEO with dynamic JSX content or we need more performance in load time for a frontend pages. And for that cases Facebook developers made React.js in that way so it can be rendered on Server Side too, using Node.js basic functionality.
So the flow is almost similar to this one
This is helping to display HTML content faster than React will render it, and it is helping to give some content to Search Engine bots or website crawlers.
... read the whole story at medium.com.