module: simpler esm loading

This simplifies loading the experimental modules. Instead of always
checking for them we should eagerly load the functions in case the
experimental modules flag is passed through.

PR-URL: #26974
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Signed-off-by: Beth Griggs <Bethany.Griggs@uk.ibm.com>

lib/internal/modules/cjs/loader.js

@@ -61,13 +61,6 @@ let asyncESM;
 let ModuleJob;
 let createDynamicModule;
 
-function lazyLoadESM() {
-  asyncESM = require('internal/process/esm_loader');
-  ModuleJob = require('internal/modules/esm/module_job');
-  createDynamicModule = require(
-    'internal/modules/esm/create_dynamic_module');
-}
-
 const {
   CHAR_UPPERCASE_A,
   CHAR_LOWERCASE_A,
@@ -673,7 +666,6 @@ Module.prototype.load = function(filename) {
   this.loaded = true;
 
   if (experimentalModules) {
-    if (asyncESM === undefined) lazyLoadESM();
     const ESMLoader = asyncESM.ESMLoader;
     const url = `${pathToFileURL(filename)}`;
     const module = ESMLoader.moduleMap.get(url);
@@ -740,7 +732,6 @@ Module.prototype._compile = function(content, filename) {
       lineOffset: 0,
       displayErrors: true,
       importModuleDynamically: experimentalModules ? async (specifier) => {
-        if (asyncESM === undefined) lazyLoadESM();
         const loader = await asyncESM.loaderPromise;
         return loader.import(specifier, normalizeReferrerURL(filename));
       } : undefined,
@@ -767,7 +758,6 @@ Module.prototype._compile = function(content, filename) {
       const { callbackMap } = internalBinding('module_wrap');
       callbackMap.set(compiledWrapper, {
         importModuleDynamically: async (specifier) => {
-          if (asyncESM === undefined) lazyLoadESM();
           const loader = await asyncESM.loaderPromise;
           return loader.import(specifier, normalizeReferrerURL(filename));
         }
@@ -847,7 +837,6 @@ Module._extensions['.node'] = function(module, filename) {
 };
 
 if (experimentalModules) {
-  if (asyncESM === undefined) lazyLoadESM();
   Module._extensions['.mjs'] = function(module, filename) {
     throw new ERR_REQUIRE_ESM(filename);
   };
@@ -857,7 +846,6 @@ if (experimentalModules) {
 Module.runMain = function() {
   // Load the main module--the command line argument.
   if (experimentalModules) {
-    if (asyncESM === undefined) lazyLoadESM();
     asyncESM.loaderPromise.then((loader) => {
       return loader.import(pathToFileURL(process.argv[1]).pathname);
     })
@@ -940,3 +928,11 @@ Module._initPaths();
 
 // Backwards compatibility
 Module.Module = Module;
+
+// We have to load the esm things after module.exports!
+if (experimentalModules) {
+  asyncESM = require('internal/process/esm_loader');
+  ModuleJob = require('internal/modules/esm/module_job');
+  createDynamicModule = require(
+    'internal/modules/esm/create_dynamic_module');
+}