module: load ESM helpers eagerly in the snapshot

joyeecheung · sxa · commit a53b51df3819 · 2026-06-18T21:12:36.000+01:00
Since the ESM loader is captured in the snapshot now, there's no need to lazy load the helpers. Load them eagerly to capture them into the snapshot. This also reduces the noise coming out of --print-bytecode since we no longer compile the helper functions at run time. Signed-off-by: Joyee Cheung <joyeec9h3@gmail.com> PR-URL: #63550 Reviewed-By: Chengzhong Wu <legendecas@gmail.com> Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
diff --git a/lib/internal/modules/esm/loader.js b/lib/internal/modules/esm/loader.js
@@ -14,7 +14,8 @@ const {
   hardenRegExp,
 } = primordials;
 
-
+const { LoadCache, ResolveCache } = require('internal/modules/esm/module_map');
+const { ModuleJob, ModuleJobSync } = require('internal/modules/esm/module_job');
 // This is needed to avoid cycles in esm/resolve <-> cjs/loader
 const {
   kIsExecuting,
@@ -81,24 +82,6 @@ const { isPromise } = require('internal/util/types');
  * @typedef {import('url').URL} URL
  */
 
-/**
- * Lazy loads the module_map module and returns a new instance of ResolveCache.
- * @returns {import('./module_map.js').ResolveCache}
- */
-function newResolveCache() {
-  const { ResolveCache } = require('internal/modules/esm/module_map');
-  return new ResolveCache();
-}
-
-/**
- * Generate a load cache (to store the final result of a load-chain for a particular module).
- * @returns {import('./module_map.js').LoadCache}
- */
-function newLoadCache() {
-  const { LoadCache } = require('internal/modules/esm/module_map');
-  return new LoadCache();
-}
-
 const { translators } = require('internal/modules/esm/translators');
 const { defaultResolve } = require('internal/modules/esm/resolve');
 const { defaultLoadSync, throwUnknownModuleFormat } = require('internal/modules/esm/load');
@@ -157,12 +140,12 @@ class ModuleLoader {
   /**
    * Registry of resolved specifiers
    */
-  #resolveCache = newResolveCache();
+  #resolveCache = new ResolveCache();
 
   /**
    * Registry of loaded modules, akin to `require.cache`
    */
-  loadCache = newLoadCache();
+  loadCache = new LoadCache();
 
   /**
    * @see {AsyncLoaderHooks.isForAsyncLoaderHookWorker}
@@ -235,7 +218,6 @@ class ModuleLoader {
    * @returns {Promise<object>} The module object.
    */
   async executeModuleJob(url, wrap, isEntryPoint = false) {
-    const { ModuleJob } = require('internal/modules/esm/module_job');
     const module = await onImport.tracePromise(async () => {
       const job = new ModuleJob(this, url, undefined, wrap, kEvaluationPhase, false, false, kImportInImportedESM);
       this.loadCache.set(url, undefined, job);
@@ -354,7 +336,6 @@ class ModuleLoader {
     const wrap = compileSourceTextModule(url, source, this);
     const inspectBrk = (isMain && getOptionValue('--inspect-brk'));
 
-    const { ModuleJobSync } = require('internal/modules/esm/module_job');
     job = new ModuleJobSync(this, url, kEmptyObject, wrap, kEvaluationPhase, isMain, inspectBrk,
                             kImportInRequiredESM);
     this.loadCache.set(url, kImplicitTypeAttribute, job);
@@ -584,7 +565,6 @@ class ModuleLoader {
       assert(moduleOrModulePromise instanceof ModuleWrap, `Expected ModuleWrap for loading ${url}`);
     }
 
-    const { ModuleJob, ModuleJobSync } = require('internal/modules/esm/module_job');
     // TODO(joyeecheung): use ModuleJobSync for kRequireInImportedCJS too.
     const ModuleJobCtor = (requestType === kImportInRequiredESM ? ModuleJobSync : ModuleJob);
     const isMain = (parentURL === undefined);
diff --git a/test/parallel/test-bootstrap-modules.js b/test/parallel/test-bootstrap-modules.js
@@ -133,6 +133,8 @@ if (isMainThread) {
     'NativeModule internal/modules/esm/load',
     'NativeModule internal/modules/esm/resolve',
     'NativeModule internal/modules/esm/translators',
+    'NativeModule internal/modules/esm/module_job',
+    'NativeModule internal/modules/esm/module_map',
     'NativeModule url',
   ].forEach(expected.beforePreExec.add.bind(expected.beforePreExec));
 } else {  // Worker.
