It was the "view as a (pure) function of your model" approach that was architecturally new in react.

This article explains it using a bit of react jargon (action, store, dispatcher) which is kind of unnecessary - but that's what I got from a quick google:

https://medium.com/@asif-ali/react-architecture-vs-mvc-unidi....

React Architecture vs. MVC: Unidirectional Flow Advantage.