web components are reactive. They have a render pattern similar to React's render function. Granted, web-components are much more wonky than React, but the functionality is there.

It seems best practice to use the component's attributes directly. So the component is subscribed to its attributes change lifecycle and renders updates.

Looking into the history of reactive updates, we find that it started with simple javascript commands helped kickstart most of it.

https://en.wikipedia.org/wiki/Ajax_(programming)

The idea of reactivity started in the 1990's in production.

When Gmail was released this technology is what made a website behave like a desktop app (plus the huge amount of storage)

If we were to look into today's equivalent of doing this, it might be surprising what exists in the standard libraries.