From f61b00175e7bcd4a5c06ab2d70bdf7d9387acada Mon Sep 17 00:00:00 2001
From: neverland <chenjiahan@youzan.com>
Date: Wed, 10 Aug 2022 08:31:46 +0800
Subject: [PATCH] fix(ConfigProvider): should remove theme class on unmount
 (#10898)

---
 .../src/config-provider/ConfigProvider.tsx    | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/packages/vant/src/config-provider/ConfigProvider.tsx b/packages/vant/src/config-provider/ConfigProvider.tsx
index 7f60b8ccd..d3af4bef1 100644
--- a/packages/vant/src/config-provider/ConfigProvider.tsx
+++ b/packages/vant/src/config-provider/ConfigProvider.tsx
@@ -2,6 +2,9 @@ import {
   watch,
   provide,
   computed,
+  onActivated,
+  onDeactivated,
+  onBeforeUnmount,
   defineComponent,
   type PropType,
   type InjectionKey,
@@ -57,14 +60,27 @@ export default defineComponent({
     });
 
     if (inBrowser) {
+      const addTheme = () => {
+        document.body.classList.add(`van-theme-${props.theme}`);
+      };
+      const removeTheme = (theme = props.theme) => {
+        document.body.classList.remove(`van-theme-${theme}`);
+      };
+
       watch(
         () => props.theme,
         (newVal, oldVal) => {
-          document.body.classList.remove(`van-theme-${oldVal}`);
-          document.body.classList.add(`van-theme-${newVal}`);
+          if (oldVal) {
+            removeTheme(oldVal);
+          }
+          addTheme();
         },
         { immediate: true }
       );
+
+      onActivated(addTheme);
+      onDeactivated(removeTheme);
+      onBeforeUnmount(removeTheme);
     }
 
     provide(CONFIG_PROVIDER_KEY, props);