Properly resolve polyfills in Vite 8

Author: davidmyersdev

src/index.ts

@@ -11,6 +11,7 @@ import {
   type TransformHook,
   compareModuleNames,
   isEnabled,
+  isModuleName,
   isNodeProtocolImport,
   toRegExp,
   withoutNodeProtocol,
@@ -197,6 +198,32 @@ export const nodePolyfills = (options: PolyfillOptions = {}): Plugin[] => {
     ...((isEnabled(optionsResolved.globals.process, 'dev')) ? [require.resolve('vite-plugin-node-polyfills/shims/process')] : []),
   ]
 
+  const resolvePlugin: Plugin = {
+    name: 'vite-plugin-node-polyfills:resolve',
+    enforce: 'pre',
+    resolveId: {
+      // @ts-expect-error -- hook filters are only supported in Vite 6.3.0+
+      filter: { id: /\/$/ },
+      async handler(source, importer, opts) {
+        const stripped = source.slice(0, -1)
+
+        if (!isModuleName(stripped)) {
+          return
+        }
+
+        if (!optionsResolved.protocolImports && isNodeProtocolImport(stripped)) {
+          return
+        }
+
+        if (isExcluded(stripped)) {
+          return
+        }
+
+        return this.resolve(stripped, importer, { skipSelf: true, ...opts })
+      },
+    },
+  }
+
   const globalShimsBanner = [
     ...((isEnabled(optionsResolved.globals.Buffer, 'dev')) ? globalShimBanners.buffer : []),
     ...((isEnabled(optionsResolved.globals.global, 'dev')) ? globalShimBanners.global : []),
@@ -223,9 +250,11 @@ export const nodePolyfills = (options: PolyfillOptions = {}): Plugin[] => {
   const plugin: Plugin = {
     name: 'vite-plugin-node-polyfills',
     config(config, env) {
+      const isBuild = env.command === 'build'
       const isDev = env.command === 'serve'
       // @ts-expect-error - this.meta.rolldownVersion only exists with rolldown-vite 7+
       const isRolldownVite = !!this?.meta?.rolldownVersion
+      const isNativeInjectAvailable = isBuild && isRolldownVite
 
       // https://github.com/niksy/node-stdlib-browser/blob/3e7cd7f3d115ac5c4593b550e7d8c4a82a0d4ac4/README.md?plain=1#L203-L209
       const defines = {
@@ -241,7 +270,6 @@ export const nodePolyfills = (options: PolyfillOptions = {}): Plugin[] => {
         ...(isEnabled(optionsResolved.globals.process, 'build') ? { process: 'vite-plugin-node-polyfills/shims/process' } : {}),
       }
 
-      const isNativeInjectAvailable = env.command === 'build' && isRolldownVite
       rawInjectPlugin = (Object.keys(shimsToInject).length > 0 && !isNativeInjectAvailable) ? inject(shimsToInject) as Plugin : false
       if (rawInjectPlugin === false) {
         delete injectPlugin.transform
@@ -286,6 +314,7 @@ export const nodePolyfills = (options: PolyfillOptions = {}): Plugin[] => {
                     define: defines,
                   },
                   plugins: [
+                    resolvePlugin,
                     {
                       name: 'vite-plugin-node-polyfills:optimizer',
                       banner: isDev ? globalShimsBanner : undefined,
@@ -335,6 +364,7 @@ export const nodePolyfills = (options: PolyfillOptions = {}): Plugin[] => {
     },
   }
   return [
+    resolvePlugin,
     injectPlugin,
     plugin,
   ]

src/utils.ts

@@ -1,4 +1,4 @@
-import type stdLibBrowser from 'node-stdlib-browser'
+import stdLibBrowser from 'node-stdlib-browser'
 import { type Plugin } from 'vite'
 
 export type BuildTarget = 'build' | 'dev'
@@ -18,6 +18,10 @@ export const isEnabled = (value: BooleanOrBuildTarget, target: BuildTarget) => {
   return value === target
 }
 
+export const isModuleName = (name: string): name is ModuleName => {
+  return name in stdLibBrowser
+}
+
 export const isNodeProtocolImport = (name: string) => {
   return name.startsWith('node:')
 }