Merge pull request #3508 from pmndrs/fix-react19-act

Fix builds failing from React.act being removed from the production bundle

Author: krispya

.changeset/thick-rice-switch.md

@@ -0,0 +1,5 @@
+---
+'@react-three/fiber': patch
+---
+
+Fix failing builds for production when React.act is unavailable. This fixes issues found in [email protected] and up.

packages/fiber/src/core/utils.tsx

@@ -31,7 +31,13 @@ export type Act = <T = any>(cb: () => Promise<T>) => Promise<T>
 /**
  * Safely flush async effects when testing, simulating a legacy root.
  */
-export const act: Act = (React as any).act
+export const act: Act = (cb) => {
+  if ('act' in React) {
+    return React.act(cb)
+  }
+
+  throw new Error('act(...) is not supported in production builds of React')
+}
 
 export type Camera = (THREE.OrthographicCamera | THREE.PerspectiveCamera) & { manual?: boolean }
 export const isOrthographicCamera = (def: Camera): def is THREE.OrthographicCamera =>