[mostlylurks]

Yes, but the fact that react uses the DOM is because that is what the very restricted platform gives you out of the box, and opting for other options would have several disadvantages that are purely the result of those other options not being directly provided by the platform itself. A reactive UI library (like react) could very easily be implemented on top of other UI paradigms as well, including decidedly non-OOP ones. There's nothing special about object oriented UI systems that motivates reactive UI libraries to use them except for the fact that that's what the underlying platform provides because that was what was in fashion when the platform was taking shape.

[ithkuil]

Yes you can implement an object model in a purely functional language.

[ithkuil]

To add on that: there is a duality between closures and OOP methods