Streamline

lib/internal/modules/run_main.js

@@ -9,19 +9,15 @@ const path = require('path');
 
 /**
  * Get the absolute path to the main entry point.
+ * Only used in `--experimental-default-type=commonjs` mode.
  * @param {string} main - Entry point path
  */
 function resolveMainPath(main) {
-  /** @type {string} */
-  let mainPath;
-  if (getOptionValue('--experimental-default-type') === 'module') {
-    mainPath = path.resolve(main);
-  } else {
-    // Extension searching for the main entry point is supported only in legacy mode.
-    // Module._findPath is monkey-patchable here.
-    const { Module } = require('internal/modules/cjs/loader');
-    mainPath = Module._findPath(path.resolve(main), null, true);
-  }
+  // Note extension resolution for the main entry point can be deprecated in a
+  // future major.
+  // Module._findPath is monkey-patchable here.
+  const { Module } = require('internal/modules/cjs/loader');
+  let mainPath = Module._findPath(path.resolve(main), null, true);
   if (!mainPath) { return; }
 
   const preserveSymlinksMain = getOptionValue('--preserve-symlinks-main');
@@ -35,11 +31,10 @@ function resolveMainPath(main) {
 
 /**
  * Determine whether the main entry point should be loaded through the ESM Loader.
+ * Only used in `--experimental-default-type=commonjs` mode.
  * @param {string} mainPath - Absolute path to the main entry point
  */
 function shouldUseESMLoader(mainPath) {
-  if (getOptionValue('--experimental-default-type') === 'module') { return true; }
-
   /**
    * @type {string[]} userLoaders A list of custom loaders registered by the user
    * (or an empty list when none have been registered).
@@ -64,7 +59,7 @@ function shouldUseESMLoader(mainPath) {
 
 /**
  * Run the main entry point through the ESM Loader.
- * @param {string} mainPath - Absolute path for the main entry point
+ * @param {string} mainPath - Path to the main entry point, either absolute or relative to CWD
  */
 function runMainESM(mainPath) {
   const { loadESM } = require('internal/process/esm_loader');
@@ -102,6 +97,11 @@ async function handleMainPromise(promise) {
  * @param {string} main - Resolved absolute path for the main entry point, if found
  */
 function executeUserEntryPoint(main = process.argv[1]) {
+  if (getOptionValue('--experimental-default-type') === 'module') {
+    runMainESM(main);
+    return;
+  }
+
   const resolvedMain = resolveMainPath(main);
   const useESMLoader = shouldUseESMLoader(resolvedMain);
   if (useESMLoader) {

test/es-module/test-esm-type-flag-errors.mjs

@@ -26,7 +26,7 @@ describe('--experimental-default-type=module should not support extension search
       cwd: fixtures.path('es-modules/package-without-type'),
     });
 
-    match(stderr, /ENOENT/);
+    match(stderr, /ERR_MODULE_NOT_FOUND/);
     strictEqual(stdout, '');
     strictEqual(code, 1);
     strictEqual(signal, null);