Problem

When a webpage is loaded with DevTools open, the browser automatically attempts to fetch .map files if a sourceMappingURL comment is present at the end of each JavaScript file.

//# sourceMappingURL=xxx.js.map

Vite includes this comment by default when build.sourcemap is set to true.
In our case, sourcemaps are removed after the build process by the Sentry plugin, so these requests result in a large number of 404s and can cause performance issues.

Solution

Set build.sourcemap to 'hidden' in vite.config.ts.
https://vite.dev/config/build-options.html#build-sourcemap

This ensures that sourcemaps are still generated, but the sourceMappingURL comment is no longer injected into the final JS output — preventing unnecessary network requests triggered by DevTools.