From 0aac165d4ebbf05d87894f86c9e1cf4d92d8a9a3 Mon Sep 17 00:00:00 2001
From: neverland <chenjiahan@youzan.com>
Date: Sun, 4 Sep 2022 21:00:18 +0800
Subject: [PATCH] fix(Picker): failed to update value in some cases (#11009)

---
 packages/vant/src/picker/Picker.tsx | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/packages/vant/src/picker/Picker.tsx b/packages/vant/src/picker/Picker.tsx
index 3d240a707..f8d14e5a7 100644
--- a/packages/vant/src/picker/Picker.tsx
+++ b/packages/vant/src/picker/Picker.tsx
@@ -245,10 +245,17 @@ export default defineComponent({
       { immediate: true }
     );
 
+    // preserve last emitted model value
+    // when props.modelValue is updated by parent component,
+    // the new value should be compared with the last emitted value
+    let lastEmittedModelValue: Numeric[];
     watch(
       () => props.modelValue,
       (newValues) => {
-        if (!isSameValue(newValues, selectedValues.value)) {
+        if (
+          !isSameValue(newValues, selectedValues.value) &&
+          !isSameValue(newValues, lastEmittedModelValue)
+        ) {
           selectedValues.value = newValues.slice(0);
         }
       },
@@ -258,7 +265,8 @@ export default defineComponent({
       selectedValues,
       (newValues) => {
         if (!isSameValue(newValues, props.modelValue)) {
-          emit('update:modelValue', newValues.slice(0));
+          lastEmittedModelValue = newValues.slice(0);
+          emit('update:modelValue', lastEmittedModelValue);
         }
       },
       { immediate: true }