Discussion about resolving a BrowserslistError in package.json

This error isn't specific to Sanity, but it's a common issue in modern JavaScript projects including Sanity Studio setups. The BrowserslistError: Unknown browser query 'dead' happens when your project configuration references the "dead" browser query, but an outdated version of Browserslist in your dependency tree doesn't recognize it.

The "dead" query was introduced in Browserslist v4.21.0 (July 2022) to identify browsers that are officially discontinued with very low usage. Even if your direct packages are updated, nested dependencies can still pull in older Browserslist versions.

Here's how to fix it:

1. Force update Browserslist across your entire dependency tree:

# For npm
npm install browserslist@latest --save-dev
npx npm-force-resolutions

# For yarn
yarn add browserslist@latest --dev
yarn install --force

# For pnpm
pnpm add -D browserslist@latest
pnpm install --force

2. Clear all caches and reinstall (most reliable solution):

# npm
rm -rf node_modules package-lock.json
npm cache clean --force
npm install

# yarn
rm -rf node_modules yarn.lock
yarn cache clean
yarn install

# pnpm
rm -rf node_modules pnpm-lock.yaml
pnpm store prune
pnpm install

The cache clearing approach is often necessary because package managers can cache resolved dependency versions, and simply running npm update won't always catch deeply nested outdated packages.

3. Use npm overrides/resolutions (if the problem persists):

Add this to your package.json to force a minimum Browserslist version throughout your entire dependency tree:

{
  "overrides": {
    "browserslist": "^4.21.0"
  }
}

For Yarn, use resolutions instead:

{
  "resolutions": {
    "browserslist": "^4.21.0"
  }
}

4. Temporary workaround (if you need to build immediately):

If you have a .browserslistrc file or browserslist field in package.json, you can temporarily replace the "dead" query with an equivalent:

# Instead of:
not dead

# Use:
> 0.2%
not ie <= 11
not op_mini all

After applying these fixes, your build tools (Next.js, Vite, or Sanity Studio's bundler) should recognize the "dead" query properly. The cache clearing approach (solution #2) combined with forcing Browserslist updates typically resolves this issue permanently.