useDeferredValue Initial Config

Hiding the "Stale" State

The Shift: useDeferredValue is used to keep the UI responsive during heavy updates. Previously, you couldn't set an initial value, so the first render might show undefined or flash.

👀 Preview

useDeferredValue can now accept an initial value, preventing undefined flashes on first render.

📚 Explanation

`useDeferredValue` in React 19 accepts an optional second parameter for the initial value. This prevents undefined or flashy initial states, making the transition smoother and more predictable.