fix: cancel queued batch updates when unmounted in useBatcher

src/hooks/useEffectState.tsx

@@ -15,15 +15,28 @@ type NotifyEffectUpdate = (callback: UpdateCallbackFunc) => void;
 export function useBatcher() {
   // Updater Trigger
   const updateFuncRef = React.useRef<UpdateCallbackFunc[]>(null);
+  const destroyedRef = React.useRef(false);
+
+  React.useEffect(() => {
+    destroyedRef.current = false;
+    return () => {
+      destroyedRef.current = true;
+      updateFuncRef.current = null;
+    };
+  }, []);
 
   // Notify update
   const notifyEffectUpdate: NotifyEffectUpdate = callback => {
+    if (destroyedRef.current) {
+      return;
+    }
+
     if (!updateFuncRef.current) {
       updateFuncRef.current = [];
 
       channelUpdate(() => {
         unstable_batchedUpdates(() => {
-          updateFuncRef.current.forEach(fn => {
+          updateFuncRef.current?.forEach(fn => {
             fn();
           });
           updateFuncRef.current = null;

tests/useEffectState.spec.tsx

@@ -0,0 +1,39 @@
+import { act, renderHook } from '@testing-library/react';
+import { useBatcher } from '../src/hooks/useEffectState';
+
+describe('useEffectState / useBatcher', () => {
+  it('should process updates after StrictMode re-establishes effects', async () => {
+    const callback = jest.fn();
+    const { result } = renderHook(() => useBatcher(), {
+      reactStrictMode: true,
+    });
+
+    result.current(callback);
+
+    await act(async () => {
+      await new Promise(resolve => setTimeout(resolve, 50));
+    });
+
+    expect(callback).toHaveBeenCalledTimes(1);
+  });
+
+  it('should clean up queued updates on unmount', async () => {
+    let notify: any;
+    let updateCalled = false;
+    const { unmount } = renderHook(() => {
+      notify = useBatcher();
+    });
+
+    notify(() => {
+      updateCalled = true;
+    });
+
+    unmount();
+
+    await act(async () => {
+      await new Promise(resolve => setTimeout(resolve, 50));
+    });
+
+    expect(updateCalled).toBe(false);
+  });
+});