From a42c5a7423a8ebd5e3b241e40edd643259614203 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=99=B3=E5=BB=B7=E5=AE=89?=
 <73953029+nrps9909@users.noreply.github.com>
Date: Fri, 28 Aug 2026 18:09:46 +0800
Subject: [PATCH] fix: guard missing React version export
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Signed-off-by: 陳廷安 <73953029+nrps9909@users.noreply.github.com>
---
 src/ref.ts                |  2 +-
 tests/ref-version.test.ts | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 tests/ref-version.test.ts

diff --git a/src/ref.ts b/src/ref.ts
index fd9513b9..9dd8c41d 100644
--- a/src/ref.ts
+++ b/src/ref.ts
@@ -4,7 +4,7 @@ import { ForwardRef, isMemo } from 'react-is';
 import useMemo from './hooks/useMemo';
 import isFragment from './React/isFragment';
 
-const ReactMajorVersion = Number(version.split('.')[0]);
+const ReactMajorVersion = Number(version?.split('.')[0]);
 
 export const fillRef = <T>(ref: React.Ref<T>, node: T) => {
   if (typeof ref === 'function') {
diff --git a/tests/ref-version.test.ts b/tests/ref-version.test.ts
new file mode 100644
index 00000000..5c438909
--- /dev/null
+++ b/tests/ref-version.test.ts
@@ -0,0 +1,10 @@
+jest.mock('react', () => ({
+  ...jest.requireActual('react'),
+  version: undefined,
+}));
+
+describe('ref without a React version export', () => {
+  it('loads without throwing', () => {
+    expect(() => jest.requireActual('../src/ref')).not.toThrow();
+  });
+});