From 35d91f4e18ccb72cbf39a86fe8f39060f0bf075e Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Thu, 13 Feb 2020 17:27:52 -0500
Subject: [PATCH] fix(runtime-core): handle component updates with only
 class/style bindings

---
 .../runtime-core/src/componentRenderUtils.ts  | 20 +++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/packages/runtime-core/src/componentRenderUtils.ts b/packages/runtime-core/src/componentRenderUtils.ts
index 5e60ad3975..a105ce987f 100644
--- a/packages/runtime-core/src/componentRenderUtils.ts
+++ b/packages/runtime-core/src/componentRenderUtils.ts
@@ -172,12 +172,20 @@ export function shouldUpdateComponent(
     if (patchFlag & PatchFlags.FULL_PROPS) {
       // presence of this flag indicates props are always non-null
       return hasPropsChanged(prevProps!, nextProps!)
-    } else if (patchFlag & PatchFlags.PROPS) {
-      const dynamicProps = nextVNode.dynamicProps!
-      for (let i = 0; i < dynamicProps.length; i++) {
-        const key = dynamicProps[i]
-        if (nextProps![key] !== prevProps![key]) {
-          return true
+    } else {
+      if (patchFlag & PatchFlags.CLASS) {
+        return prevProps!.class === nextProps!.class
+      }
+      if (patchFlag & PatchFlags.STYLE) {
+        return hasPropsChanged(prevProps!.style, nextProps!.style)
+      }
+      if (patchFlag & PatchFlags.PROPS) {
+        const dynamicProps = nextVNode.dynamicProps!
+        for (let i = 0; i < dynamicProps.length; i++) {
+          const key = dynamicProps[i]
+          if (nextProps![key] !== prevProps![key]) {
+            return true
+          }
         }
       }
     }
-- 
2.47.3