From 9e6da5b842631b776c1890fb4d267a47733d6ab7 Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Fri, 6 Feb 2026 18:21:01 +0100
Subject: [PATCH 1/3] lib: remove top-level getOptionValue() calls in
 lib/internal/modules

---
 lib/internal/modules/esm/formats.js     | 70 -------------------------
 lib/internal/modules/esm/get_format.js  | 64 +++++++++++++++++++---
 lib/internal/modules/esm/resolve.js     |  7 +--
 lib/internal/process/pre_execution.js   |  3 ++
 lib/internal/repl/completion.js         |  2 +-
 test/parallel/test-bootstrap-modules.js |  1 +
 6 files changed, 65 insertions(+), 82 deletions(-)
 delete mode 100644 lib/internal/modules/esm/formats.js

diff --git a/lib/internal/modules/esm/formats.js b/lib/internal/modules/esm/formats.js
deleted file mode 100644
index 6a18bd992fa1d9..00000000000000
--- a/lib/internal/modules/esm/formats.js
+++ /dev/null
@@ -1,70 +0,0 @@
-'use strict';
-
-const {
-  RegExpPrototypeExec,
-} = primordials;
-
-const { getOptionValue } = require('internal/options');
-const { getValidatedPath } = require('internal/fs/utils');
-const fsBindings = internalBinding('fs');
-const { internal: internalConstants } = internalBinding('constants');
-
-const experimentalAddonModules = getOptionValue('--experimental-addon-modules');
-
-const extensionFormatMap = {
-  '__proto__': null,
-  '.cjs': 'commonjs',
-  '.js': 'module',
-  '.json': 'json',
-  '.mjs': 'module',
-  '.wasm': 'wasm',
-};
-
-if (experimentalAddonModules) {
-  extensionFormatMap['.node'] = 'addon';
-}
-
-if (getOptionValue('--strip-types')) {
-  extensionFormatMap['.ts'] = 'module-typescript';
-  extensionFormatMap['.mts'] = 'module-typescript';
-  extensionFormatMap['.cts'] = 'commonjs-typescript';
-}
-
-/**
- * @param {string} mime
- * @returns {string | null}
- */
-function mimeToFormat(mime) {
-  if (
-    RegExpPrototypeExec(
-      /^\s*(text|application)\/javascript\s*(;\s*charset=utf-?8\s*)?$/i,
-      mime,
-    ) !== null
-  ) { return 'module'; }
-  if (mime === 'application/json') { return 'json'; }
-  if (mime === 'application/wasm') { return 'wasm'; }
-  return null;
-}
-
-/**
- * For extensionless files in a `module` package scope, we check the file contents to disambiguate between ES module
- * JavaScript and Wasm.
- * We do this by taking advantage of the fact that all Wasm files start with the header `0x00 0x61 0x73 0x6d` (`_asm`).
- * @param {URL} url
- * @returns {'wasm'|'module'}
- */
-function getFormatOfExtensionlessFile(url) {
-  const path = getValidatedPath(url);
-  switch (fsBindings.getFormatOfExtensionlessFile(path)) {
-    case internalConstants.EXTENSIONLESS_FORMAT_WASM:
-      return 'wasm';
-    default:
-      return 'module';
-  }
-}
-
-module.exports = {
-  extensionFormatMap,
-  getFormatOfExtensionlessFile,
-  mimeToFormat,
-};
diff --git a/lib/internal/modules/esm/get_format.js b/lib/internal/modules/esm/get_format.js
index 48ccb97a6244ea..4f334c7d88c336 100644
--- a/lib/internal/modules/esm/get_format.js
+++ b/lib/internal/modules/esm/get_format.js
@@ -9,13 +9,63 @@ const {
   StringPrototypeSlice,
 } = primordials;
 const { getOptionValue } = require('internal/options');
-const {
-  extensionFormatMap,
-  getFormatOfExtensionlessFile,
-  mimeToFormat,
-} = require('internal/modules/esm/formats');
+const { getValidatedPath } = require('internal/fs/utils');
+const fsBindings = internalBinding('fs');
+const { internal: internalConstants } = internalBinding('constants');
+
+const extensionFormatMap = {
+  '__proto__': null,
+  '.cjs': 'commonjs',
+  '.js': 'module',
+  '.json': 'json',
+  '.mjs': 'module',
+  '.wasm': 'wasm',
+};
+
+function initializeExtensionFormatMap() {
+  if (getOptionValue('--experimental-addon-modules')) {
+    extensionFormatMap['.node'] = 'addon';
+  }
+
+  if (getOptionValue('--strip-types')) {
+    extensionFormatMap['.ts'] = 'module-typescript';
+    extensionFormatMap['.mts'] = 'module-typescript';
+    extensionFormatMap['.cts'] = 'commonjs-typescript';
+  }
+}
 
-const detectModule = getOptionValue('--experimental-detect-module');
+/**
+ * @param {string} mime
+ * @returns {string | null}
+ */
+function mimeToFormat(mime) {
+  if (
+    RegExpPrototypeExec(
+      /^\s*(text|application)\/javascript\s*(;\s*charset=utf-?8\s*)?$/i,
+      mime,
+    ) !== null
+  ) { return 'module'; }
+  if (mime === 'application/json') { return 'json'; }
+  if (mime === 'application/wasm') { return 'wasm'; }
+  return null;
+}
+
+/**
+ * For extensionless files in a `module` package scope, we check the file contents to disambiguate between ES module
+ * JavaScript and Wasm.
+ * We do this by taking advantage of the fact that all Wasm files start with the header `0x00 0x61 0x73 0x6d` (`_asm`).
+ * @param {URL} url
+ * @returns {'wasm'|'module'}
+ */
+function getFormatOfExtensionlessFile(url) {
+  const path = getValidatedPath(url);
+  switch (fsBindings.getFormatOfExtensionlessFile(path)) {
+    case internalConstants.EXTENSIONLESS_FORMAT_WASM:
+      return 'wasm';
+    default:
+      return 'module';
+  }
+}
 const { containsModuleSyntax } = internalBinding('contextify');
 const { getPackageScopeConfig, getPackageType } = require('internal/modules/package_json_reader');
 const { fileURLToPath } = require('internal/url');
@@ -35,6 +85,7 @@ const protocolHandlers = {
  * @returns {'module'|'commonjs'}
  */
 function detectModuleFormat(source, url) {
+  const detectModule = getOptionValue('--experimental-detect-module');
   if (!source) { return detectModule ? null : 'commonjs'; }
   if (!detectModule) { return 'commonjs'; }
   return containsModuleSyntax(`${source}`, fileURLToPath(url), url) ? 'module' : 'commonjs';
@@ -216,4 +267,5 @@ module.exports = {
   defaultGetFormatWithoutErrors,
   extensionFormatMap,
   extname,
+  initializeExtensionFormatMap,
 };
diff --git a/lib/internal/modules/esm/resolve.js b/lib/internal/modules/esm/resolve.js
index cc1230648881d8..473398bf29bcdf 100644
--- a/lib/internal/modules/esm/resolve.js
+++ b/lib/internal/modules/esm/resolve.js
@@ -29,9 +29,6 @@ const { realpathSync } = require('fs');
 const { getOptionValue } = require('internal/options');
 // Do not eagerly grab .manifest, it may be in TDZ
 const { sep, posix: { relative: relativePosixPath }, resolve } = require('path');
-const preserveSymlinks = getOptionValue('--preserve-symlinks');
-const preserveSymlinksMain = getOptionValue('--preserve-symlinks-main');
-const inputTypeFlag = getOptionValue('--input-type');
 const { URL, pathToFileURL, fileURLToPath, isURL, URLParse } = require('internal/url');
 const { getCWDURL, setOwnProperty } = require('internal/util');
 const { canParse: URLCanParse } = internalBinding('url');
@@ -982,7 +979,7 @@ function defaultResolve(specifier, context = {}) {
     // input, to avoid user confusion over how expansive the effect of the
     // flag should be (i.e. entry point only, package scope surrounding the
     // entry point, etc.).
-    if (inputTypeFlag) { throw new ERR_INPUT_TYPE_NOT_ALLOWED(); }
+    if (getOptionValue('--input-type')) { throw new ERR_INPUT_TYPE_NOT_ALLOWED(); }
   }
 
   conditions = getConditionsSet(conditions);
@@ -992,7 +989,7 @@ function defaultResolve(specifier, context = {}) {
       specifier,
       parentURL,
       conditions,
-      isMain ? preserveSymlinksMain : preserveSymlinks,
+      isMain ? getOptionValue('--preserve-symlinks-main') : getOptionValue('--preserve-symlinks'),
     );
   } catch (error) {
     // Try to give the user a hint of what would have been the
diff --git a/lib/internal/process/pre_execution.js b/lib/internal/process/pre_execution.js
index 0902536708bf1d..ebb44b935e1b58 100644
--- a/lib/internal/process/pre_execution.js
+++ b/lib/internal/process/pre_execution.js
@@ -161,6 +161,9 @@ function prepareExecution(options) {
     assert(!initializeModules);
   }
 
+  const { initializeExtensionFormatMap } = require('internal/modules/esm/get_format');
+  initializeExtensionFormatMap();
+
   setupVmModules();
   if (initializeModules) {
     initializeModuleLoaders({ shouldSpawnLoaderHookWorker, shouldPreloadModules });
diff --git a/lib/internal/repl/completion.js b/lib/internal/repl/completion.js
index a16b7af0d1732c..8587e5e5b2333b 100644
--- a/lib/internal/repl/completion.js
+++ b/lib/internal/repl/completion.js
@@ -48,7 +48,7 @@ const CJSModule = require('internal/modules/cjs/loader').Module;
 
 const {
   extensionFormatMap,
-} = require('internal/modules/esm/formats');
+} = require('internal/modules/esm/get_format');
 
 const path = require('path');
 const fs = require('fs');
diff --git a/test/parallel/test-bootstrap-modules.js b/test/parallel/test-bootstrap-modules.js
index ae96258e95d89d..4c8be110e065b0 100644
--- a/test/parallel/test-bootstrap-modules.js
+++ b/test/parallel/test-bootstrap-modules.js
@@ -118,6 +118,7 @@ expected.beforePreExec = new Set([
 ]);
 
 expected.atRunTime = new Set([
+  'NativeModule internal/modules/esm/get_format',
   'NativeModule internal/process/pre_execution',
 ]);
 

From 0659ac3b1b6981236b5e456643f3a3f9f16302c1 Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Fri, 6 Feb 2026 18:41:49 +0100
Subject: [PATCH 2/3] lib: reduce cycles in esm loader and load it in snapshot

---
 .../bootstrap/switches/is_main_thread.js      |  1 +
 lib/internal/modules/esm/loader.js            | 30 ++++---------------
 lib/internal/modules/esm/resolve.js           |  9 ++----
 lib/internal/modules/esm/translators.js       | 17 ++++-------
 test/parallel/test-bootstrap-modules.js       |  8 ++++-
 5 files changed, 21 insertions(+), 44 deletions(-)

diff --git a/lib/internal/bootstrap/switches/is_main_thread.js b/lib/internal/bootstrap/switches/is_main_thread.js
index 74486ba5310b78..06ac27c8486963 100644
--- a/lib/internal/bootstrap/switches/is_main_thread.js
+++ b/lib/internal/bootstrap/switches/is_main_thread.js
@@ -296,6 +296,7 @@ require('util');
 require('url'); // eslint-disable-line no-restricted-modules
 internalBinding('module_wrap');
 require('internal/modules/cjs/loader');
+require('internal/modules/esm/loader');
 require('internal/modules/esm/utils');
 
 // Needed to refresh the time origin.
diff --git a/lib/internal/modules/esm/loader.js b/lib/internal/modules/esm/loader.js
index 41513d1b9f3658..37eb267e154cc7 100644
--- a/lib/internal/modules/esm/loader.js
+++ b/lib/internal/modules/esm/loader.js
@@ -65,8 +65,6 @@ const {
   validateLoadSloppy,
 } = require('internal/modules/customization_hooks');
 
-let defaultResolve, defaultLoadSync;
-
 const { tracingChannel } = require('diagnostics_channel');
 const onImport = tracingChannel('module.import');
 
@@ -100,19 +98,9 @@ function newLoadCache() {
   return new LoadCache();
 }
 
-let _translators;
-function lazyLoadTranslators() {
-  _translators ??= require('internal/modules/esm/translators');
-  return _translators;
-}
-
-/**
- * Lazy-load translators to avoid potentially unnecessary work at startup (ex if ESM is not used).
- * @returns {import('./translators.js').Translators}
- */
-function getTranslators() {
-  return lazyLoadTranslators().translators;
-}
+const { translators } = require('internal/modules/esm/translators');
+const { defaultResolve } = require('internal/modules/esm/resolve');
+const { defaultLoadSync, throwUnknownModuleFormat } = require('internal/modules/esm/load');
 
 /**
  * Generate message about potential race condition caused by requiring a cached module that has started
@@ -181,11 +169,6 @@ class ModuleLoader {
    */
   loadCache = newLoadCache();
 
-  /**
-   * Methods which translate input code or other information into ES modules
-   */
-  translators = getTranslators();
-
   /**
    * @see {AsyncLoaderHooks.isForAsyncLoaderHookWorker}
    * Shortcut to this.#asyncLoaderHooks.isForAsyncLoaderHookWorker.
@@ -459,7 +442,7 @@ class ModuleLoader {
   #translate(url, translateContext, parentURL) {
     const { translatorKey, format } = translateContext;
     this.validateLoadResult(url, format);
-    const translator = getTranslators().get(translatorKey);
+    const translator = translators.get(translatorKey);
 
     if (!translator) {
       throw new ERR_UNKNOWN_MODULE_FORMAT(translatorKey, url);
@@ -710,7 +693,7 @@ class ModuleLoader {
     if (cachedResult != null) {
       return cachedResult;
     }
-    defaultResolve ??= require('internal/modules/esm/resolve').defaultResolve;
+
     const result = defaultResolve(specifier, context);
     this.#resolveCache.set(requestKey, parentURL, result);
     return result;
@@ -787,7 +770,6 @@ class ModuleLoader {
     if (this.#asyncLoaderHooks?.loadSync) {
       return this.#asyncLoaderHooks.loadSync(url, context);
     }
-    defaultLoadSync ??= require('internal/modules/esm/load').defaultLoadSync;
     return defaultLoadSync(url, context);
   }
 
@@ -813,7 +795,7 @@ class ModuleLoader {
 
   validateLoadResult(url, format) {
     if (format == null) {
-      require('internal/modules/esm/load').throwUnknownModuleFormat(url, format);
+      throwUnknownModuleFormat(url, format);
     }
   }
 
diff --git a/lib/internal/modules/esm/resolve.js b/lib/internal/modules/esm/resolve.js
index 473398bf29bcdf..d253a3ff67280c 100644
--- a/lib/internal/modules/esm/resolve.js
+++ b/lib/internal/modules/esm/resolve.js
@@ -46,8 +46,7 @@ const {
   ERR_UNSUPPORTED_DIR_IMPORT,
   ERR_UNSUPPORTED_RESOLVE_REQUEST,
 } = require('internal/errors').codes;
-
-const { Module: CJSModule } = require('internal/modules/cjs/loader');
+const { defaultGetFormatWithoutErrors } = require('internal/modules/esm/get_format');
 const { getConditionsSet } = require('internal/modules/esm/utils');
 const packageJsonReader = require('internal/modules/package_json_reader');
 const internalFsBinding = internalBinding('fs');
@@ -870,6 +869,7 @@ function moduleResolve(specifier, base, conditions, preserveSymlinks) {
  */
 function resolveAsCommonJS(specifier, parentURL) {
   try {
+    const { Module: CJSModule } = require('internal/modules/cjs/loader');
     const parent = fileURLToPath(parentURL);
     const tmpModule = new CJSModule(parent, null);
     tmpModule.paths = CJSModule._nodeModulePaths(parent);
@@ -1043,8 +1043,3 @@ module.exports = {
   packageResolve,
   throwIfInvalidParentURL,
 };
-
-// cycle
-const {
-  defaultGetFormatWithoutErrors,
-} = require('internal/modules/esm/get_format');
diff --git a/lib/internal/modules/esm/translators.js b/lib/internal/modules/esm/translators.js
index f45defe9dad88a..8cf008d52ab380 100644
--- a/lib/internal/modules/esm/translators.js
+++ b/lib/internal/modules/esm/translators.js
@@ -13,7 +13,7 @@ const {
   StringPrototypeReplaceAll,
   StringPrototypeSlice,
   StringPrototypeStartsWith,
-  globalThis: { WebAssembly },
+  globalThis,
 } = primordials;
 
 const {
@@ -57,16 +57,7 @@ const { maybeCacheSourceMap } = require('internal/source_map/source_map_cache');
 const moduleWrap = internalBinding('module_wrap');
 const { ModuleWrap, kEvaluationPhase } = moduleWrap;
 
-// Lazy-loading to avoid circular dependencies.
-let getSourceSync;
-/**
- * @param {Parameters<typeof import('./load').getSourceSync>[0]} url
- * @returns {ReturnType<typeof import('./load').getSourceSync>}
- */
-function getSource(url) {
-  getSourceSync ??= require('internal/modules/esm/load').getSourceSync;
-  return getSourceSync(url);
-}
+const { getSourceSync } = require('internal/modules/esm/load');
 
 const { parse: cjsParse } = internalBinding('cjs_lexer');
 
@@ -210,7 +201,7 @@ function createCJSModuleWrap(url, translateContext, parentURL, loadCJS = loadCJS
   const isMain = (parentURL === undefined);
   const filename = urlToFilename(url);
   // In case the source was not provided by the `load` step, we need fetch it now.
-  source = stringify(source ?? getSource(new URL(url)).source);
+  source = stringify(source ?? getSourceSync(new URL(url)).source);
 
   const { exportNames, module } = cjsPreparseModuleExports(filename, source, sourceFormat);
   cjsCache.set(url, module);
@@ -516,6 +507,8 @@ translators.set('json', function jsonStrategy(url, translateContext) {
 const wasmInstances = new SafeWeakMap();
 translators.set('wasm', function(url, translateContext) {
   const { source } = translateContext;
+  // WebAssembly global is not available during snapshot building, so we need to get it lazily.
+  const { WebAssembly } = globalThis;
   assertBufferSource(source, false, 'load');
 
   debug(`Translating WASMModule ${url}`, translateContext);
diff --git a/test/parallel/test-bootstrap-modules.js b/test/parallel/test-bootstrap-modules.js
index 4c8be110e065b0..a16573124d733f 100644
--- a/test/parallel/test-bootstrap-modules.js
+++ b/test/parallel/test-bootstrap-modules.js
@@ -115,10 +115,16 @@ expected.beforePreExec = new Set([
   'NativeModule internal/modules/run_main',
   'NativeModule internal/net',
   'NativeModule internal/dns/utils',
+  'NativeModule internal/modules/esm/assert',
+  'NativeModule internal/modules/esm/loader',
+  'Internal Binding cjs_lexer',
+  'NativeModule internal/modules/esm/get_format',
+  'NativeModule internal/modules/esm/load',
+  'NativeModule internal/modules/esm/resolve',
+  'NativeModule internal/modules/esm/translators',
 ]);
 
 expected.atRunTime = new Set([
-  'NativeModule internal/modules/esm/get_format',
   'NativeModule internal/process/pre_execution',
 ]);
 

From 71c535af26fdbd8691d839cebd94723a1396b4c8 Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Fri, 6 Feb 2026 19:28:52 +0100
Subject: [PATCH 3/3] benchmark: add startup benchmark for ESM entrypoint

---
 benchmark/fixtures/empty.mjs           |  0
 benchmark/fixtures/import-builtins.mjs | 34 ++++++++++++++++++++++++++
 benchmark/misc/startup-core.js         | 10 +++++---
 3 files changed, 40 insertions(+), 4 deletions(-)
 create mode 100644 benchmark/fixtures/empty.mjs
 create mode 100644 benchmark/fixtures/import-builtins.mjs

diff --git a/benchmark/fixtures/empty.mjs b/benchmark/fixtures/empty.mjs
new file mode 100644
index 00000000000000..e69de29bb2d1d6
diff --git a/benchmark/fixtures/import-builtins.mjs b/benchmark/fixtures/import-builtins.mjs
new file mode 100644
index 00000000000000..03feaa4887c362
--- /dev/null
+++ b/benchmark/fixtures/import-builtins.mjs
@@ -0,0 +1,34 @@
+import 'node:async_hooks';
+import 'node:assert';
+import 'node:buffer';
+import 'node:child_process';
+import 'node:console';
+import 'node:constants';
+import 'node:crypto';
+import 'node:cluster';
+import 'node:dgram';
+import 'node:dns';
+import 'node:domain';
+import 'node:events';
+import 'node:fs';
+import 'node:http';
+import 'node:http2';
+import 'node:https';
+import 'node:module';
+import 'node:net';
+import 'node:os';
+import 'node:path';
+import 'node:perf_hooks';
+import 'node:process';
+import 'node:querystring';
+import 'node:readline';
+import 'node:repl';
+import 'node:stream';
+import 'node:string_decoder';
+import 'node:timers';
+import 'node:tls';
+import 'node:tty';
+import 'node:url';
+import 'node:util';
+import 'node:vm';
+import 'node:zlib';
diff --git a/benchmark/misc/startup-core.js b/benchmark/misc/startup-core.js
index 053a1ec0cbff8f..414b00176ad2c2 100644
--- a/benchmark/misc/startup-core.js
+++ b/benchmark/misc/startup-core.js
@@ -7,9 +7,11 @@ let Worker;  // Lazy loaded in main
 
 const bench = common.createBenchmark(main, {
   script: [
-    'benchmark/fixtures/require-builtins',
-    'test/fixtures/semicolon',
-    'test/fixtures/snapshot/typescript',
+    'benchmark/fixtures/empty.mjs',
+    'benchmark/fixtures/import-builtins.mjs',
+    'benchmark/fixtures/require-builtins.js',
+    'test/fixtures/semicolon.js',
+    'test/fixtures/snapshot/typescript.js',
   ],
   mode: ['process', 'worker'],
   n: [30],
@@ -58,7 +60,7 @@ function spawnWorker(script, bench, state) {
 }
 
 function main({ n, script, mode }) {
-  script = path.resolve(__dirname, '../../', `${script}.js`);
+  script = path.resolve(__dirname, '../../', `${script}`);
   const warmup = 3;
   const state = { n, finished: -warmup };
   if (mode === 'worker') {