From 85af1398637ee91c6ebabb73bf42250320311e19 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thorsten=20L=C3=BCnborg?= <t.luenborg@googlemail.com>
Date: Wed, 13 Apr 2022 12:20:39 +0200
Subject: [PATCH] fix(runtime-dom): properly handle style properties with
 undefined values (#5348)

fix #5322
---
 packages/runtime-dom/__tests__/patchStyle.spec.ts | 13 ++++++++++++-
 packages/runtime-dom/src/modules/style.ts         |  1 +
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/packages/runtime-dom/__tests__/patchStyle.spec.ts b/packages/runtime-dom/__tests__/patchStyle.spec.ts
index 92b30aa5815..409d6936eaf 100644
--- a/packages/runtime-dom/__tests__/patchStyle.spec.ts
+++ b/packages/runtime-dom/__tests__/patchStyle.spec.ts
@@ -37,7 +37,18 @@ describe(`runtime-dom: style patching`, () => {
 
   it('remove if falsy value', () => {
     const el = document.createElement('div')
-    patchProp(el, 'style', { color: 'red' }, { color: undefined })
+    patchProp(el, 'style', null, {
+      color: undefined,
+      borderRadius: null
+    })
+    expect(el.style.cssText.replace(/\s/g, '')).toBe('')
+
+    patchProp(
+      el,
+      'style',
+      { color: 'red' },
+      { color: null, borderRadius: undefined }
+    )
     expect(el.style.cssText.replace(/\s/g, '')).toBe('')
   })
 
diff --git a/packages/runtime-dom/src/modules/style.ts b/packages/runtime-dom/src/modules/style.ts
index a9cc67ba5e2..f4924ea2ec6 100644
--- a/packages/runtime-dom/src/modules/style.ts
+++ b/packages/runtime-dom/src/modules/style.ts
@@ -45,6 +45,7 @@ function setStyle(
   if (isArray(val)) {
     val.forEach(v => setStyle(style, name, v))
   } else {
+    if (val == null) val = ''
     if (name.startsWith('--')) {
       // custom property definition
       style.setProperty(name, val)