From 64dc7ff5c3678dedaa05b7fa1bd86344df99d148 Mon Sep 17 00:00:00 2001
From: Herrington Darkholme
 <2883231+HerringtonDarkholme@users.noreply.github.com>
Date: Mon, 13 Sep 2021 19:30:56 +0800
Subject: [PATCH] fix(compiler-core): only merge true handlers

Users can provide :onClick as event handler since vnode structure is flat. However, only /^on[^a-z]/ is accepted as event pros.
This fix makes dedupeProperties consistent with the runtime.
---
 packages/compiler-core/src/transforms/transformElement.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/compiler-core/src/transforms/transformElement.ts b/packages/compiler-core/src/transforms/transformElement.ts
index c471d2a4b84..f9c7d73571d 100644
--- a/packages/compiler-core/src/transforms/transformElement.ts
+++ b/packages/compiler-core/src/transforms/transformElement.ts
@@ -806,7 +806,7 @@ function dedupeProperties(properties: Property[]): Property[] {
     const name = prop.key.content
     const existing = knownProps.get(name)
     if (existing) {
-      if (name === 'style' || name === 'class' || name.startsWith('on')) {
+      if (name === 'style' || name === 'class' || isOn(name)) {
         mergeAsArray(existing, prop)
       }
       // unexpected duplicate, should have emitted error during parse