SSR dev server fails with "module is not defined" for CJS dependencies (void-elements, highlight.js, etc.)

[ThyeeZz]

Description

When migrating a Next.js Pages Router project to vinext, vinext dev fails with 500 Internal Server Error because Vite 8's ESModulesEvaluator cannot handle CommonJS dependencies that use module.exports.

Reproduction

1. A Next.js project with common CJS dependencies (e.g. react-i18next → html-parse-stringify → void-elements, or highlight.js)
2. Run npx vinext init then npx vinext dev
3. Visit http://localhost:3000/

Error

Error when evaluating SSR module /src/pages/index.tsx: module is not defined
at eval (node_modules/void-elements/index.js:8:1)
at ESModulesEvaluator.runInlinedModule (vite/dist/node/module-runner.js:988:161)

ReferenceError: module is not defined
at node_modules/void-elements/index.js:6:1

After externaling void-elements, the same error occurs for highlight.js/lib/core.js, and so on for other CJS-only packages.

Attempted workarounds

Config	Result
ssr.noExternal: ['void-elements', ...]	Same error, CJS not transformed
ssr.noExternal: true	Same error
ssr.external: ['void-elements', ...]	Fixes that package, but next CJS dep fails (whack-a-mole)
ssr.external: true	Even react itself gets externalized and fails
ssr.external: [/node_modules/]	Vite 8 rejects RegExp: Value is non of these types True, Array<T>

Root cause

Vite 8's ESModulesEvaluator (used by SSRCompatModuleRunner) runs module code in strict ESM scope where module is not defined. CJS packages that use module.exports = ... fail immediately. Vite's CJS→ESM transform doesn't seem to kick in
for these dependencies during SSR dev.

Environment

• Node.js: v22.22.1
• vinext: 0.0.31
• Vite: 8.0.1
• Package manager: pnpm 10.32.1
• OS: macOS (darwin-arm64)

Affected packages (partial list)

• void-elements (via react-i18next → html-parse-stringify)
• highlight.js
• react itself (react/index.js uses module.exports)
• Many others — most npm packages still ship CJS

Expected behavior

vinext should handle CJS dependencies transparently in SSR dev mode, similar to how Next.js webpack does.