There are a lot of React state libraries that do similar things with Proxies. I think the part that is not as emphasized is how that reactivity extends to the view. Instead of re-rendering components it uses that knowledge to directly update portions of the DOM. So while MobX, Valtio, Jotai, Recoil etc localize change in React, they still feed into the whole VDOM React cycle, instead of just updating exactly what changes. It's not a characteristic of these libraries but the fact they feed into React.