Use enhanced-resolve to load files

package.json

@@ -43,6 +43,7 @@
     "ast-types": "^0.14.2",
     "clear-module": "^4.1.2",
     "cpy-cli": "^5.0.0",
+    "enhanced-resolve": "^5.17.1",
     "esbuild": "^0.19.8",
     "escalade": "^3.1.1",
     "import-sort-style-module": "^6.0.0",

src/config.ts

@@ -17,7 +17,7 @@ import loadConfigFallback from 'tailwindcss/loadConfig'
 import resolveConfigFallback from 'tailwindcss/resolveConfig'
 import type { RequiredConfig } from 'tailwindcss/types/config.js'
 import { expiringMap } from './expiring-map.js'
-import { resolveFrom, resolveIn } from './resolve'
+import { resolveJsFrom } from './resolve'
 import type { ContextContainer } from './types'
 
 let sourceToPathMap = new Map<string, string | null>()
@@ -104,7 +104,7 @@ async function loadTailwindConfig(
   let tailwindConfig: RequiredConfig = { content: [] }
 
   try {
-    let pkgFile = resolveIn('tailwindcss/package.json', [baseDir])
+    let pkgFile = resolveJsFrom(baseDir, 'tailwindcss/package.json')
     let pkgDir = path.dirname(pkgFile)
 
     try {
@@ -160,7 +160,8 @@ function createLoader<T>({
 
   async function loadFile(id: string, base: string) {
     try {
-      let resolved = resolveFrom(base, id)
+      let resolved = resolveJsFrom(base, id)
+
       let url = pathToFileURL(resolved)
       url.searchParams.append('t', cacheKey)
 
@@ -180,7 +181,8 @@ async function loadV4(
   entryPoint: string | null,
 ) {
   // Import Tailwind — if this is v4 it'll have APIs we can use directly
-  let pkgPath = resolveIn('tailwindcss', [baseDir])
+  let pkgPath = resolveJsFrom(baseDir, 'tailwindcss')
+
   let tw = await import(pathToFileURL(pkgPath).toString())
 
   // This is not Tailwind v4

src/resolve.ts

@@ -1,8 +1,25 @@
-import { createRequire as req } from 'node:module'
-import resolveFrom from 'resolve-from'
+import fs from 'node:fs'
+import { fileURLToPath } from 'node:url'
+import { CachedInputFileSystem, ResolverFactory } from 'enhanced-resolve'
 import { expiringMap } from './expiring-map'
 
-const localRequire = req(import.meta.url)
+const fileSystem = new CachedInputFileSystem(fs, 30_000)
+
+const esmResolver = ResolverFactory.createResolver({
+  fileSystem,
+  useSyncFileSystemCalls: true,
+  extensions: ['.mjs', '.js'],
+  mainFields: ['module'],
+  conditionNames: ['node', 'import'],
+})
+
+const cjsResolver = ResolverFactory.createResolver({
+  fileSystem,
+  useSyncFileSystemCalls: true,
+  extensions: ['.js', '.cjs'],
+  mainFields: ['main'],
+  conditionNames: ['node', 'require'],
+})
 
 // This is a long-lived cache for resolved modules whether they exist or not
 // Because we're compatible with a large number of plugins, we need to check
@@ -11,17 +28,11 @@ const localRequire = req(import.meta.url)
 // failed module resolutions making repeated checks very expensive.
 const resolveCache = expiringMap<string, string | null>(30_000)
 
-export function resolveIn(id: string, paths: string[]) {
-  return localRequire.resolve(id, {
-    paths,
-  })
-}
-
 export function maybeResolve(name: string) {
   let modpath = resolveCache.get(name)
 
   if (modpath === undefined) {
-    modpath = freshMaybeResolve(name)
+    modpath = resolveJsFrom(fileURLToPath(import.meta.url), name)
     resolveCache.set(name, modpath)
   }
 
@@ -39,12 +50,10 @@ export async function loadIfExists<T>(name: string): Promise<T | null> {
   return null
 }
 
-function freshMaybeResolve(name: string) {
+export function resolveJsFrom(base: string, id: string): string {
   try {
-    return localRequire.resolve(name)
+    return esmResolver.resolveSync({}, base, id) || id
   } catch (err) {
-    return null
+    return cjsResolver.resolveSync({}, base, id) || id
   }
 }
-
-export { resolveFrom }