refactor: remove CJS and env var Babel transforms, let Vite handle natively#3767
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bartlomieju merged 9 commits intoApr 25, 2026
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Remove the 78-line Babel `inlineEnvVarsPlugin` and replace it with Vite's built-in `define` configuration for `process.env.FRESH_PUBLIC_*` and `import.meta.env.FRESH_PUBLIC_*` patterns. A lightweight regex-based Vite plugin handles `Deno.env.get()` calls which can't use `define`. Env file loading moved from `configResolved` to `config` so define entries are available during Vite's config resolution phase. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Instead of transforming CJS to ESM via a 960-line Babel plugin, let Vite handle CJS packages natively by: 1. Removing `meta.deno` from file:// resolved paths in deno.ts so Vite loads npm packages from disk instead of through @deno/loader 2. Removing `noExternal: true` so Vite externalizes npm packages in SSR dev mode (Node.js handles CJS natively via require()) 3. Removing `noDiscovery: true` so Vite's dependency optimizer can pre-bundle CJS packages for the client 4. Applying resolve.alias before Deno resolution so react -> preact/compat works even when packages are externalized Also converts local .cjs test fixtures to ESM since they no longer go through the CJS transform. Deletes ~1,800 lines. Eliminates the #1 source of npm compat bugs (#3619, #3653, #3505, #3478, #3449). Known regressions (2 tests): radix-ui and remote island need investigation for duplicate preact instances with externalization. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
…l for radix-ui Apply Vite's resolve.alias config (e.g. react -> preact/compat) in deno.ts before calling @deno/loader, so the alias works even when packages are externalized in SSR mode. Also add noExternal for @radix-ui packages in the SSR environment since they depend on React compat aliases being applied. WIP: radix test still failing — alias format from Vite config needs further investigation. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
- Add lightweight CJS shim in deno.ts load hook for dev mode: wraps CJS files in node_modules with module/exports/require so Vite's SSR module runner can evaluate them. Only ~30 lines vs the old 960-line Babel CJS transform. Only runs in dev mode — build mode uses Rollup's @rollup/plugin-commonjs natively. - Restore ssr.noExternal: true so resolve.alias (react -> preact/compat) is applied consistently in SSR. Without it, Node.js require() bypasses aliases and loads real react@19.1.1. - Apply resolve.alias in deno.ts resolveId before @deno/loader runs, so aliased specifiers (react, react-dom) resolve to preact/compat through the Deno resolution pipeline. - Remove environment-level noExternal (was duplicated). Test results: 35/36 dev tests pass, 31/31 build tests pass. The 1 failing test (remote island) is pre-existing on main. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Instead of disabling the dependency optimizer entirely (noDiscovery), exclude only preact ecosystem packages from optimization. This allows CJS packages like mime-db to be pre-bundled for the browser while preventing duplicate preact instances when remote (JSR) islands resolve deps to /@fs/ paths. Also extends the CJS shim to work in both SSR (with createRequire) and client (with stub require) environments. All dev server tests pass (35/36 — 1 pre-existing flaky failure on remote island that also fails on main). All 31 build tests pass. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
The dependency optimizer causes duplicate preact instances when remote (JSR) islands resolve deps to /@fs/ paths while the optimizer bundles to /.vite/deps/. Restore noDiscovery: true to prevent this. For CJS packages used in client-side islands (like mime-db), convert require() calls to ESM import statements via regex so browsers can load them. The SSR shim continues to use Node.js createRequire. All tests pass: 36/36 dev, 31/31 build, 15/15 patches. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
The `links` field referenced a sibling directory that only exists on the author's machine, causing `deno install` to fail in CI. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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…3793) Closes #3794 Fixes a regression from #3767 where CJS npm packages fail with `exports is not defined` in dev mode. - The old heuristic (`code.includes("export ")`) was fooled by the word "export" appearing in comments of CJS files — e.g. `@opentelemetry/api` has `// TODO: Remove ProxyTracerProvider export in the next major version.` which caused the CJS shim to be skipped entirely - Replaces the naive string check with two-layer detection: 1. **Package.json `type` field** (Node.js semantics): `.cjs` → always CJS, `.js` → CJS unless nearest `package.json` has `"type": "module"`. Results cached per directory. 2. **ESM statement regex fallback**: for dual CJS/ESM packages that ship ESM in `.js` without `"type": "module"` (e.g. `@opentelemetry/api`, `preact-render-to-string`), detects actual ESM syntax including minified forms like `import{` and `export*from` - Adds a test importing from a real CJS npm package (`qs`) in `node_modules` — the existing "CJS test" fixtures were local ESM files that never exercised the shim path
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## Summary Reverts two commits that broke CJS package handling in dev mode: - Reverts #3793 (CJS detection regex fix) - Reverts #3767 (removal of Babel CJS→ESM transform) The simplified CJS shim introduced in #3767 has two fundamental issues: 1. **Detection**: the heuristic (`code.includes("export ")`) is fooled by comments containing "export" 2. **Named exports**: the shim only provides `export default module.exports`, so `import { trace } from "@opentelemetry/api"` returns `undefined` (#3797) The Babel-based transform handled both correctly. Bringing it back until we can replace it with a proper solution using `deno_ast`'s CJS parser.
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Summary
Replace Babel env var transforms with Vite's native
define—process.env.FRESH_PUBLIC_*andimport.meta.env.FRESH_PUBLIC_*now use Vite's built-indefineconfig.Deno.env.get()calls use a lightweight regex-based transform (~10 lines vs 78-line Babel plugin).Remove the 960-line CJS→ESM Babel transform — Instead of transforming CJS to ESM via Babel, let Vite handle CJS packages natively:
@rollup/plugin-commonjshandles CJS (always has, but was bypassed bydeno.tsloading through@deno/loader)node_modulesCJS files withmodule/exports/requireso Vite's SSR module runner can evaluate themdeno.tsno longer attachesmeta.denoto file:// resolved paths — Vite loads them from disk directlyRemove
noDiscovery: true— Vite's dependency optimizer can now pre-bundle CJS packages for the clientFix React compat aliasing — Apply
resolve.alias(react → preact/compat) indeno.tsbefore@deno/loaderresolution, so the alias works even when packages are non-external in SSRNet: ~2,050 lines deleted, ~150 lines added.
Fixes #3619, fixes #3653, fixes #3505, fixes #3478, fixes #3449.