refactor(build): remove vite-plugin-commonjs

packages/vinext/package.json

@@ -179,7 +179,6 @@
     "@vinext/types": "workspace:^",
     "ipaddr.js": "catalog:",
     "magic-string": "catalog:",
-    "vite-plugin-commonjs": "catalog:",
     "web-vitals": "catalog:"
   },
   "devDependencies": {

packages/vinext/src/config/next-config.ts

@@ -10,7 +10,7 @@ import fs from "node:fs";
 import { fileURLToPath } from "node:url";
 import { randomUUID } from "node:crypto";
 import type { PluginOption } from "vite";
-import commonjs from "vite-plugin-commonjs";
+import { createCommonJsPlugin } from "../plugins/commonjs.js";
 import { PHASE_DEVELOPMENT_SERVER } from "vinext/shims/constants";
 import { normalizePageExtensions } from "../routing/file-matcher.js";
 import { getHtmlLimitedBotRegex } from "../utils/html-limited-bots.js";
@@ -1018,7 +1018,7 @@ export async function loadNextConfig(
   // name; it does not shadow an installed package with a baseUrl-local file.
   const useNativeTsconfigPaths = !!tsconfigBaseUrl;
 
-  // Symlink-resolved config path, used by the `commonjs()` filter below to
+  // Symlink-resolved config path, used by the CommonJS filter below to
   // exclude the config file itself. macOS uses /private/var symlinks, so
   // string-compare without realpath would falsely include the config.
   const normalizedConfigPath = safeRealpath(path.resolve(configPath));
@@ -1046,11 +1046,8 @@ export async function loadNextConfig(
         // externalized, so a baseUrl-local file does not shadow a package of the
         // same name.
         ...(useNativeTsconfigPaths ? { tsconfigPaths: true } : {}),
-        // Include `.cjs` and `.cts` so `vite-plugin-commonjs` recognises
-        // those extensions (the plugin keys off `config.resolve.extensions`,
-        // which on Vite defaults to `[.mjs, .js, .mts, .ts, .jsx, .tsx,
-        // .json]` — no CJS extensions). This also lets the runner's resolver
-        // find `./foo` style imports that resolve to a `.cjs`/`.cts` sibling.
+        // Include `.cjs` and `.cts` so the runner's resolver and the CommonJS
+        // transform recognise extensionless sibling imports in those formats.
         extensions: [".mjs", ".js", ".cjs", ".mts", ".ts", ".cts", ".jsx", ".tsx", ".json"],
       },
       // Only inject CJS globals for TypeScript config flavours. Next.js
@@ -1059,7 +1056,7 @@ export async function loadNextConfig(
       // configs are loaded through Node and already have `require`/`module`,
       // and `.mjs` configs are explicitly ESM-only.
       //
-      // Pair that with `vite-plugin-commonjs` (the same plugin used for
+      // Pair that with the same internal CommonJS transform used for
       // application code in index.ts) so sibling imports like `.cjs`/`.cts`,
       // or `.js`/`.ts` files that assign to `module.exports`, are converted
       // to ESM before Vite's runner evaluates them. The default `filter`
@@ -1093,16 +1090,12 @@ export async function loadNextConfig(
           },
         },
         ...(isTypeScriptConfig ? [cjsGlobalsInjectorPlugin(configPath)] : []),
-        commonjs({
-          filter: (id: string) => {
+        createCommonJsPlugin({
+          shouldTransform: (_environment, _code, id) => {
             const idPath = id.startsWith("file://") ? fileURLToPath(id) : id.split("?")[0];
             const resolvedId = safeRealpath(path.resolve(idPath));
             if (resolvedId === normalizedConfigPath) return false;
-            // Returning `true` forces the transform to run even for ids
-            // inside `node_modules` (default behaviour skips them);
-            // `undefined` falls through to the plugin's default for
-            // user code.
-            return id.includes("node_modules") ? true : undefined;
+            return true;
           },
         }),
       ],

packages/vinext/src/index.ts

@@ -2,6 +2,7 @@ import type {
   Alias,
   CSSModulesOptions,
   DevEnvironment,
+  Environment,
   HotUpdateOptions,
   Logger,
   Plugin,
@@ -276,7 +277,7 @@ import { createRequire } from "node:module";
 import fs from "node:fs";
 import { createHash, randomBytes } from "node:crypto";
 import { getPagesPreviewModeId } from "./server/pages-preview.js";
-import commonjs from "vite-plugin-commonjs";
+import { createCommonJsPlugin } from "./plugins/commonjs.js";
 import { createIgnoreDynamicRequestsPlugin } from "./plugins/ignore-dynamic-requests.js";
 import { createTransformCache } from "./plugins/transform-cache.js";
 import {
@@ -554,6 +555,32 @@ function commonjsTransformFilter(
   return undefined;
 }
 
+function shouldTransformCommonJs(
+  environment: Environment,
+  code: string,
+  id: string,
+  isBundledCommonJsDependency: (id: string) => boolean,
+): boolean {
+  if (
+    environment.mode === "dev" &&
+    (environment as DevEnvironment).depsOptimizer?.isOptimizedDepFile(id)
+  ) {
+    return false;
+  }
+  const cleanId = toSlash(stripViteModuleQuery(id));
+  if (isConditionalRequireScriptModuleId(cleanId)) return true;
+  const isDev = environment.mode === "dev";
+  const bundledDependency =
+    isDev &&
+    environment.config.consumer === "server" &&
+    (code.includes("__filename") || code.includes("__dirname")) &&
+    isBundledCommonJsDependency(cleanId);
+  if (bundledDependency) return true;
+  if (cleanId.includes("/node_modules/")) return false;
+  if (/\.c[jt]s$/i.test(cleanId)) return isDev;
+  return true;
+}
+
 function hasOnlyTypeSpecifiers(statement: AstStaticDependencyDeclaration): boolean {
   return (
     statement.specifiers !== undefined &&
@@ -1859,59 +1886,16 @@ export default function vinext(options: VinextOptions = {}): PluginOption[] {
     ReturnType<typeof replaceConsumerEnvironmentConditions>
   >();
 
-  // vite-plugin-commonjs calls its user filter synchronously, before its first
-  // async boundary, but the filter itself receives only an id. Bridge the
-  // current Vite environment into that call without creating per-environment
-  // plugin instances: environment plugins cannot run the configResolved hook
-  // that vite-plugin-commonjs requires to initialize its resolver.
-  let transformProjectLocalCommonJs = false;
-  let transformBundledCommonJsDependencies = false;
-  const commonJsPlugin = commonjs({
-    filter(id: string) {
-      return commonjsTransformFilter(
+  const commonJsPlugin = createCommonJsPlugin({
+    shouldTransform(environment, code, id) {
+      return shouldTransformCommonJs(
+        environment,
+        code,
         id,
-        transformProjectLocalCommonJs,
-        transformBundledCommonJsDependencies,
         importMetaUrlCapability.isBundledCommonJsDependencyId,
       );
     },
   });
-  const commonJsTransform = commonJsPlugin.transform;
-  if (typeof commonJsTransform === "function") {
-    commonJsPlugin.transform = function environmentAwareCommonJsTransform(code, id, ...args) {
-      // The independent optimizeDeps Rolldown build already converted these
-      // files to ESM. Running vite-plugin-commonjs over its output would append
-      // a second export facade (including a duplicate default export).
-      if (
-        this.environment.mode === "dev" &&
-        (this.environment as DevEnvironment).depsOptimizer?.isOptimizedDepFile(id)
-      ) {
-        return null;
-      }
-      const isDev = this.environment.mode === "dev";
-      const isServer = this.environment.config.consumer === "server";
-      const bundledDependency =
-        isDev &&
-        isServer &&
-        (code.includes("__filename") || code.includes("__dirname")) &&
-        importMetaUrlCapability.isBundledCommonJsDependencyId(id);
-      const projectLocal =
-        !bundledDependency && !id.includes("/node_modules/") && !id.includes("\\node_modules\\");
-      const previousProjectLocal = transformProjectLocalCommonJs;
-      const previous = transformBundledCommonJsDependencies;
-      transformProjectLocalCommonJs = projectLocal && isDev;
-      transformBundledCommonJsDependencies = bundledDependency;
-      try {
-        // Do not await here: the filter is consulted synchronously while this
-        // environment-scoped flag is set. The remaining async transform work
-        // does not read it, so concurrent module transforms cannot cross-talk.
-        return commonJsTransform.call(this, code, id, ...args);
-      } finally {
-        transformProjectLocalCommonJs = previousProjectLocal;
-        transformBundledCommonJsDependencies = previous;
-      }
-    };
-  }
 
   const plugins: PluginOption[] = [
     // Resolve tsconfig paths/baseUrl aliases so real-world Next.js repos
@@ -1935,12 +1919,12 @@ export default function vinext(options: VinextOptions = {}): PluginOption[] {
     // Skip project-local `.cjs`/`.cts` files during builds. `vinext init` renames CJS config
     // files to `.cjs` (e.g. `tailwind.config.js` → `tailwind.config.cjs`) when
     // it adds `"type": "module"`, and app code imports them extensionlessly
-    // (`import cfg from "../tailwind.config"`). If `vite-plugin-commonjs`
+    // (`import cfg from "../tailwind.config"`). If the CommonJS transform
     // rewrites their `module.exports` to ESM `export {}`, rolldown still infers
     // `moduleType: "cjs"` from the `.cjs`/`.cts` extension and re-parses the
     // rewritten output as CommonJS, failing with "Cannot use export statement
-    // outside a module". Returning `false` during builds makes vite-plugin-commonjs
-    // skip these project-local files so Rolldown's own CJS interop bundles them
+    // outside a module". Skip these project-local files during builds so
+    // Rolldown's own CJS interop bundles them
     // instead. Dev has no later CJS lowering pass, so transform them here.
     // Conditional `require` targets use a synthetic `.js` identity so their
     // CJS source can be converted before plugin-rsc injects ESM proxy imports.