Node v25 breaks tests with Web Storage API

[simonmysun]

Describe the bug

In Node v25.0.0 released one week ago the Web Storage API is enabled by default (nodejs/node@3312e4e946 , nodejs/node#57666), of which the behavior is however different with the browser. Now localStorage in Node is no longer undefined. Test units with Vitest with either jsdom or happy-dom environment will fail to provide methods like localStorage.getItem. I'm not completely sure it's a bug from Vitest, but I guess it's some downstream software detects its existence and gives up mocking it up. With limited exploration I find jsdom has consistent behavior in Node v25 and Node v24, so I first post it here.

A workaround for people encountering the same error: Set an environment variable to disable Web Storage API: export NODE_OPTIONS="--no-webstorage".

Reproduction

I created a minimal reproduction here: https://github.com/simonmysun/node25-vitest

The demo.test.ts will fail with Node v25 and succeed with Node v24. The docker compose file might help if you already have such environment.

System Info

vitest/3.2.4. Any system with Nodejs v25.0.0

Used Package Manager

npm

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[hi-ogawa]

Can you post the error too?

[simonmysun]

Yes sure.

With Node v25

v25.0.0

up to date, audited 95 packages in 528ms

23 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities

> node25-vitest@1.0.0 test
> vitest


 DEV  v3.2.4 /app

(node:62) Warning: `--localstorage-file` was provided without a valid path
(Use `node --trace-warnings ...` to show where the warning was created)
 ❯ demo.test.ts (1 test | 1 failed) 5ms
   × localStorage demo > foo 5ms
     → expected 'undefined' to deeply equal 'function'

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Failed Tests 1 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

 FAIL  demo.test.ts > localStorage demo > foo
AssertionError: expected 'undefined' to deeply equal 'function'

Expected: "function"
Received: "undefined"

 ❯ demo.test.ts:5:45
      3| describe('localStorage demo', () => {
      4|     it('foo', () => {
      5|         expect(typeof localStorage.getItem).toEqual('function');
       |                                             ^
      6|     });
      7| });

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯


 Test Files  1 failed (1)
      Tests  1 failed (1)
   Start at  01:49:28
   Duration  348ms (transform 18ms, setup 0ms, collect 11ms, tests 5ms, environment 206ms, prepare 33ms)

With Node v24

v24.10.0

added 46 packages, and audited 141 packages in 499ms

23 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities
npm notice
npm notice New patch version of npm available! 11.6.1 -> 11.6.2
npm notice Changelog: https://github.com/npm/cli/releases/tag/v11.6.2
npm notice To update run: npm install -g npm@11.6.2
npm notice

> node25-vitest@1.0.0 test
> vitest


 DEV  v3.2.4 /app

 ✓ demo.test.ts (1 test) 2ms
   ✓ localStorage demo > foo 1ms

 Test Files  1 passed (1)
      Tests  1 passed (1)
   Start at  01:51:02
   Duration  373ms (transform 19ms, setup 0ms, collect 14ms, tests 2ms, environment 223ms, prepare 34ms)

The outputs are generated with docker compose run --rm -it test-25 and docker compose run --rm -it test-24