dillon1000/react

[Selective Hydration] ReactDOM.unstable_scheduleHydration(domNode) (#17004)

Adds an API to explicitly prioritize hydrating the path to a particular DOM node without relying on events to do it.

The API uses the current scheduler priority to schedule it. For the same priority, the last one wins. This allows a similar effect as continuous events. This is useful for example to hydrate based on scroll position, or prioritize components that will upgrade to client-rendered-only content.

I considered having an API that explicitly overrides the current target(s). However that makes it difficult to coordinate across components in an app.

This just hydrates one target at a time but if it is blocked on I/O we could consider increasing priority of later targets too.