lib: reduce cycles in esm loader and load it in snapshot

PR-URL: #61769
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Jacob Smith <jacob@frende.me>

Author: joyeecheung

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.

lib/internal/modules/esm/loader.js

@@ -62,7 +62,7 @@ const {
   loadWithHooks: loadWithSyncHooks,
   validateLoadSloppy,
 } = require('internal/modules/customization_hooks');
-let defaultResolve, defaultLoadSync, importMetaInitializer;
+let importMetaInitializer;
 
 const { tracingChannel } = require('diagnostics_channel');
 const onImport = tracingChannel('module.import');
@@ -97,19 +97,9 @@ 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
@@ -178,18 +168,6 @@ class ModuleLoader {
    */
   loadCache = newLoadCache();
 
-  /**
-   * Methods which translate input code or other information into ES modules
-   */
-  translators = getTranslators();
-
-  /**
-   * Truthy to allow the use of `import.meta.resolve`. This is needed
-   * currently because the `Hooks` class does not have `resolveSync`
-   * implemented and `import.meta.resolve` requires it.
-   */
-  allowImportMetaResolve;
-
   /**
    * @see {AsyncLoaderHooks.isForAsyncLoaderHookWorker}
    * Shortcut to this.#asyncLoaderHooks.isForAsyncLoaderHookWorker.
@@ -464,7 +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);
@@ -715,7 +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;
@@ -792,7 +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);
   }
 
@@ -818,7 +795,7 @@ class ModuleLoader {
 
   validateLoadResult(url, format) {
     if (format == null) {
-      require('internal/modules/esm/load').throwUnknownModuleFormat(url, format);
+      throwUnknownModuleFormat(url, format);
     }
   }
 

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');

lib/internal/modules/esm/translators.js

@@ -14,7 +14,7 @@ const {
   StringPrototypeReplaceAll,
   StringPrototypeSlice,
   StringPrototypeStartsWith,
-  globalThis: { WebAssembly },
+  globalThis,
 } = primordials;
 
 const {
@@ -58,16 +58,7 @@ 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');
 
@@ -209,7 +200,7 @@ 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);
@@ -515,6 +506,8 @@ 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);

test/parallel/test-bootstrap-modules.js

@@ -115,17 +115,23 @@ expected.beforePreExec = new Set([
   'NativeModule internal/modules/run_main',
   'NativeModule internal/net',
   'NativeModule internal/dns/utils',
+  'NativeModule internal/modules/esm/get_format',
 ]);
 
 expected.atRunTime = new Set([
-  'NativeModule internal/modules/esm/get_format',
   'NativeModule internal/process/pre_execution',
 ]);
 
 const { isMainThread } = require('worker_threads');
 
 if (isMainThread) {
   [
+    'Internal Binding cjs_lexer',
+    'NativeModule internal/modules/esm/assert',
+    'NativeModule internal/modules/esm/loader',
+    'NativeModule internal/modules/esm/load',
+    'NativeModule internal/modules/esm/resolve',
+    'NativeModule internal/modules/esm/translators',
     'NativeModule url',
   ].forEach(expected.beforePreExec.add.bind(expected.beforePreExec));
 } else {  // Worker.