From 4e9bea4ffd5aafbde696dc2cf5c70422752d6ddc Mon Sep 17 00:00:00 2001
From: vaynevayne <124666577+vaynevayne@users.noreply.github.com>
Date: Sat, 10 Jun 2023 13:34:52 +0800
Subject: [PATCH] Update useMergedState.ts

inject prevState to  postState(next,prev)
---
 src/hooks/useMergedState.ts | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/hooks/useMergedState.ts b/src/hooks/useMergedState.ts
index 1e846b54..e451279e 100644
--- a/src/hooks/useMergedState.ts
+++ b/src/hooks/useMergedState.ts
@@ -22,7 +22,7 @@ export default function useMergedState<T, R = T>(
     defaultValue?: T | (() => T);
     value?: T;
     onChange?: (value: T, prevValue: T) => void;
-    postState?: (value: T) => T;
+    postState?: (value: T, prevValue?: T) => T;
   },
 ): [R, Updater<T>] {
   const { defaultValue, value, onChange, postState } = option || {};
@@ -42,13 +42,15 @@ export default function useMergedState<T, R = T>(
     }
   });
 
+  const [prevValue, setPrevValue] = useState<[T]>([mergedValue]);
+  
   const mergedValue = value !== undefined ? value : innerValue;
-  const postMergedValue = postState ? postState(mergedValue) : mergedValue;
+  const postMergedValue = postState ? postState(mergedValue,prevValue[0]) : mergedValue;
 
   // ====================== Change ======================
   const onChangeFn = useEvent(onChange);
 
-  const [prevValue, setPrevValue] = useState<[T]>([mergedValue]);
+ 
 
   useLayoutUpdateEffect(() => {
     const prev = prevValue[0];