From 5cf1111981bfc6ae668d291e346f1edf44bb5ab1 Mon Sep 17 00:00:00 2001
From: Phil Pluckthun <phil@kitten.sh>
Date: Fri, 8 Jan 2021 15:09:38 +0000
Subject: [PATCH] Add test for elements in isPlainObject and fix up check

---
 packages/styled-components/src/utils/isPlainObject.js         | 2 +-
 .../styled-components/src/utils/test/isPlainObject.test.js    | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/styled-components/src/utils/isPlainObject.js b/packages/styled-components/src/utils/isPlainObject.js
index bcb9a91d..7eb2a440 100644
--- a/packages/styled-components/src/utils/isPlainObject.js
+++ b/packages/styled-components/src/utils/isPlainObject.js
@@ -5,4 +5,4 @@ export default (x: any): boolean =>
   typeof x === 'object' &&
   (x.toString ? x.toString() : Object.prototype.toString.call(x)) === '[object Object]' &&
   /* check for reasonable markers that the object isn't an element for react & preact/compat */
-  !(x.$$typeof && (x._owner || (x.__v && x.__o)));
+  !(x.$$typeof && ('_owner' in x) || x.__v);
diff --git a/packages/styled-components/src/utils/test/isPlainObject.test.js b/packages/styled-components/src/utils/test/isPlainObject.test.js
index 845655a3..7642dc2b 100644
--- a/packages/styled-components/src/utils/test/isPlainObject.test.js
+++ b/packages/styled-components/src/utils/test/isPlainObject.test.js
@@ -29,6 +29,10 @@ it('returns false for a React component', () => {
   expect(isPlainObject(Foo)).toEqual(false);
 });
 
+it('returns false for a React element', () => {
+  expect(isPlainObject(React.createElement('div'))).toEqual(false);
+});
+
 it('returns true for an object literal created in a different context', () => {
   const context = vm.createContext({});
   vm.runInContext('object = {};', context);