esm: disable non-js exts outside package scopes

PR-URL: https://github.com/nodejs/node/pull/30501
Reviewed-By: Jan Krems <jan.krems@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>

1 files changed, 16 insertions, 20 deletions

diff --git a/lib/internal/modules/esm/default_resolve.js b/lib/internal/modules/esm/default_resolve.js
index 88af3cb5f8..5271c6a0fe 100644
--- a/lib/internal/modules/esm/default_resolve.js
+++ b/lib/internal/modules/esm/default_resolve.js
@@ -78,9 +78,19 @@ function resolve(specifier, parentURL) {
   }
 
   const isMain = parentURL === undefined;
-  if (isMain)
+  if (isMain) {
     parentURL = pathToFileURL(`${process.cwd()}/`).href;
 
+    // This is the initial entry point to the program, and --input-type has
+    // been passed as an option; but --input-type can only be used with
+    // --eval, --print or STDIN string input. It is not allowed with file
+    // 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 (typeFlag)
+      throw new ERR_INPUT_TYPE_NOT_ALLOWED();
+  }
+
   let url = moduleWrapResolve(specifier, parentURL);
 
   if (isMain ? !preserveSymlinksMain : !preserveSymlinks) {
@@ -93,27 +103,13 @@ function resolve(specifier, parentURL) {
     url.hash = old.hash;
   }
 
-  const type = getPackageType(url.href);
-
   const ext = extname(url.pathname);
-  const extMap =
-      type !== TYPE_MODULE ? legacyExtensionFormatMap : extensionFormatMap;
-  let format = extMap[ext];
-
-  if (isMain && typeFlag) {
-    // This is the initial entry point to the program, and --input-type has
-    // been passed as an option; but --input-type can only be used with
-    // --eval, --print or STDIN string input. It is not allowed with file
-    // 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.).
-    throw new ERR_INPUT_TYPE_NOT_ALLOWED();
-  }
+  let format = extensionFormatMap[ext];
+  if (ext === '.js' || (!format && isMain))
+    format = getPackageType(url.href) === TYPE_MODULE ? 'module' : 'commonjs';
   if (!format) {
-    if (isMain)
-      format = type === TYPE_MODULE ? 'module' : 'commonjs';
-    else if (esModuleSpecifierResolution === 'node')
-      format = 'commonjs';
+    if (esModuleSpecifierResolution === 'node')
+      format = legacyExtensionFormatMap[ext];
     else
       throw new ERR_UNKNOWN_FILE_EXTENSION(fileURLToPath(url));
   }