fix: properly hook builtin modules that require the 'node:' prefix

index.js

@@ -6,6 +6,7 @@ const path = require('path')
 const parse = require('module-details-from-path')
 const { fileURLToPath } = require('url')
 const { MessageChannel } = require('worker_threads')
+const { isBuiltin } = require('module')
 
 const {
   importHooks,
@@ -124,11 +125,17 @@ function Hook (modules, options, hookFn) {
 
   this._iitmHook = (name, namespace, specifier) => {
     const filename = name
-    const isBuiltin = name.startsWith('node:')
+    const isNodeUrl = name.startsWith('node:')
     let baseDir
 
-    if (isBuiltin) {
-      name = name.replace(/^node:/, '')
+    if (isNodeUrl) {
+      // Normalize builtin module name to *not* have 'node:' prefix, unless
+      // required, as it is for 'node:test' and some others.  `module.isBuiltin`
+      // is available in all Node.js versions that have node:-only modules.
+      const unprefixed = name.slice(5)
+      if (typeof isBuiltin !== 'function' || isBuiltin(unprefixed)) {
+        name = unprefixed
+      }
     } else {
       if (name.startsWith('file://')) {
         const stackTraceLimit = Error.stackTraceLimit

test/hook/v18.15-node-prefixed-only.mjs

@@ -0,0 +1,12 @@
+// Test that a builtin module that must use 'node:' prefix works.
+import { strictEqual } from 'assert'
+import Hook from '../../index.js'
+
+Hook(['node:test'], (exports, name) => {
+  if (name === 'node:test') {
+    exports.skip = 'iitm was here'
+  }
+})
+
+const { skip } = await import('node:test')
+strictEqual(skip, 'iitm was here')