Declarative state-driven UI is great, but personally, I really prefer the way e.g. knockout does it over react. It uses observables and publish/subscribe to is

Declarative state-driven UI is great, but personally, I really prefer the way e.g. knockout does it over react. It uses observables and publish/subscribe to issue updates to DOM elements directly where they're needed. You may not like knockout, but it shows how virtual DOM isn't a requirement for declarative state-driven UI.