vite-env-only denies node:fs with Intlayer

If you've used the vite-env-only plugin (as suggested in older React-Router v7 guidance) and see:

Error: [vite-env-only] Import denied* Denied by specifier pattern: /^node:/* Importer: index.html* Import: "node:fs"

…even though there’s no node:fs in your client bundle, this is a false positive.

What causes this

vite-env-only runs a Babel-based check early in the Vite graph resolution, before:

• aliasing (including Intlayer’s browser vs node mappings),
• dead-code elimination,
• SSR vs client resolution,
• virtual modules like React-Router’s.

Intlayer packages contain code that can work on both Node and the browser. At an intermediate stage, a Node built-in like node:fs may appear in the graph before Vite removes it from the client build. vite-env-only sees that and errors immediately, even though the final bundle doesn’t contain it.

React-Router and Server Modules

In the React-Router documentation about server module conventions
(https://reactrouter.com/api/framework-conventions/server-modules), the team explicitly recommends using vite-env-only to prevent server-only imports from leaking into the client bundle.

However, those conventions rely on Vite’s aliasing, conditional exports, and tree-shaking to remove server-only code. While aliasing and conditional exports are already applied, some Node-based utilities are still present in packages like @intlayer/core at that stage (even though they are never imported on the client). Because tree-shaking has not run yet, those functions are still parsed by Babel, and vite-env-only detects their node: imports and flags a false positive — even though they are correctly removed from the final client bundle.

How to fix / work around

Recommended: Remove vite-env-only

Simply remove the plugin. In many cases you don’t need it — Vite already handles client vs server imports via its own resolution.

This fixes the false node:fs denial without any changes to Intlayer.

Validate the final build instead

If you still want to ensure there are no Node built-ins in the client, do it after the build, e.g.:

pnpm buildgrep -R "node:" dist/

If there are no results, your client bundles are clean.

Summary

• vite-env-only can error on node:fs because it checks too early.
• Vite + Intlayer + React-Router’s server modules conventions normally remove server-only references correctly.
• Removing the plugin or verifying the final output is usually the best solution.