From 7c1bb9bfefdcffc5709ba2f3d57521270e5ef7f6 Mon Sep 17 00:00:00 2001
From: Guy Bedford <guybedford@gmail.com>
Date: Fri, 7 Mar 2025 13:05:09 -0800
Subject: [PATCH] esm: module.exports on CJS modules

---
 lib/internal/modules/esm/translators.js   |  8 ++++++--
 test/fixtures/es-modules/exports-cases.js | 19 ++++++++++---------
 2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/lib/internal/modules/esm/translators.js b/lib/internal/modules/esm/translators.js
index c300b0305318bd..0a8e4c9e5d3af5 100644
--- a/lib/internal/modules/esm/translators.js
+++ b/lib/internal/modules/esm/translators.js
@@ -188,10 +188,13 @@ function createCJSModuleWrap(url, source, isMain, format, loadCJS = loadCJSModul
   const { exportNames, module } = cjsPreparseModuleExports(filename, source, format);
   cjsCache.set(url, module);
 
-  const wrapperNames = [...exportNames, 'module.exports'];
+  const wrapperNames = [...exportNames];
   if (!exportNames.has('default')) {
     ArrayPrototypePush(wrapperNames, 'default');
   }
+  if (!exportNames.has('module.exports')) {
+    ArrayPrototypePush(wrapperNames, 'module.exports');
+  }
 
   if (isMain) {
     setOwnProperty(process, 'mainModule', module);
@@ -212,7 +215,8 @@ function createCJSModuleWrap(url, source, isMain, format, loadCJS = loadCJSModul
       ({ exports } = module);
     }
     for (const exportName of exportNames) {
-      if (!ObjectPrototypeHasOwnProperty(exports, exportName) || exportName === 'default') {
+      if (exportName === 'default' || exportName === 'module.exports' ||
+          !ObjectPrototypeHasOwnProperty(exports, exportName)) {
         continue;
       }
       // We might trigger a getter -> dont fail.
diff --git a/test/fixtures/es-modules/exports-cases.js b/test/fixtures/es-modules/exports-cases.js
index 94bbde74d1d40e..a8146bb12392fb 100644
--- a/test/fixtures/es-modules/exports-cases.js
+++ b/test/fixtures/es-modules/exports-cases.js
@@ -1,9 +1,10 @@
-if (global.maybe)
-  module.exports = require('../is-object');
-exports['invalid identifier'] = 'yes';
-module.exports['?invalid'] = 'yes';
-module.exports['π'] = 'yes';
-exports['\u{D83C}'] = 'no';
-exports['\u{D83C}\u{DF10}'] = 'yes';
-exports.package  = 10; // reserved word
-Object.defineProperty(exports, 'z', { value: 'yes' });
+if (global.maybe)
+  module.exports = require('../is-object');
+exports['invalid identifier'] = 'yes';
+module.exports['?invalid'] = 'yes';
+module.exports['π'] = 'yes';
+exports['\u{D83C}'] = 'no';
+exports['\u{D83C}\u{DF10}'] = 'yes';
+exports.package  = 10; // reserved word
+Object.defineProperty(exports, 'z', { value: 'yes' });
+exports['module.exports'] = 5;