fix(shallow): undefined value

[dai-shi]

close #3204

• Add a failing test
• Fix it

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Preview	Comments	Updated (UTC)
zustand-demo	Ready	Preview	Comment	Aug 19, 2025 10:40pm

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

[github-actions]

Size Change: +21 B (+0.17%)

Total Size: 12.6 kB

Filename	Size	Change
./dist/esm/vanilla/shallow.mjs	557 B	+11 B (+2.01%)
./dist/vanilla/shallow.js	568 B	+10 B (+1.79%)

ℹ️ View Unchanged

Filename	Size
./dist/esm/index.mjs	64 B
./dist/esm/middleware.mjs	3.86 kB
./dist/esm/middleware/immer.mjs	212 B
./dist/esm/react.mjs	340 B
./dist/esm/react/shallow.mjs	198 B
./dist/esm/shallow.mjs	82 B
./dist/esm/traditional.mjs	411 B
./dist/esm/vanilla.mjs	403 B
./dist/index.js	244 B
./dist/middleware.js	3.87 kB
./dist/middleware/immer.js	231 B
./dist/react.js	355 B
./dist/react/shallow.js	213 B
./dist/shallow.js	189 B
./dist/traditional.js	423 B
./dist/vanilla.js	416 B

_{compressed-size-action}

[pkg-pr-new]

demo • starter

npm i https://pkg.pr.new/zustand@3205

commit: 9170ecc