From 4cb52aaab5d2b5c1dbf74339f63e5440d873addf Mon Sep 17 00:00:00 2001
From: Geoffrey Booth <webadmin@geoffreybooth.com>
Date: Fri, 29 Sep 2023 22:01:55 -0700
Subject: [PATCH 1/5] esm: unflag extensionless javascript and wasm in module
 scope

---
 doc/api/esm.md                                |  8 +-
 lib/internal/errors.js                        |  8 +-
 lib/internal/modules/esm/get_format.js        | 32 ++-----
 .../test-esm-extensionless-esm-and-wasm.mjs   | 93 +++++++++++++++++++
 ...nsion.js => test-esm-unknown-extension.js} | 13 +--
 5 files changed, 114 insertions(+), 40 deletions(-)
 create mode 100644 test/es-module/test-esm-extensionless-esm-and-wasm.mjs
 rename test/es-module/{test-esm-unknown-or-no-extension.js => test-esm-unknown-extension.js} (65%)

diff --git a/doc/api/esm.md b/doc/api/esm.md
index bfd40556e5fcab..fa2abac7029b3d 100644
--- a/doc/api/esm.md
+++ b/doc/api/esm.md
@@ -1009,8 +1009,12 @@ _isImports_, _conditions_)
 > 5. Let _packageURL_ be the result of **LOOKUP\_PACKAGE\_SCOPE**(_url_).
 > 6. Let _pjson_ be the result of **READ\_PACKAGE\_JSON**(_packageURL_).
 > 7. If _pjson?.type_ exists and is _"module"_, then
->    1. If _url_ ends in _".js"_, then
->       1. Return _"module"_.
+>    1. If _url_ ends in _".js"_ or has no file extension, then
+>       1. If `--experimental-wasm-modules` is enabled and the file at _url_
+>          contains the header for a WebAssembly module, then
+>          1. Return _"wasm"_.
+>       2. Otherwise,
+>          1. Return _"module"_.
 >    2. Return **undefined**.
 > 8. Otherwise,
 >    1. Return **undefined**.
diff --git a/lib/internal/errors.js b/lib/internal/errors.js
index 4928ac97d51537..7111cf57f9c5d1 100644
--- a/lib/internal/errors.js
+++ b/lib/internal/errors.js
@@ -1760,12 +1760,8 @@ E('ERR_UNHANDLED_ERROR',
 E('ERR_UNKNOWN_BUILTIN_MODULE', 'No such built-in module: %s', Error);
 E('ERR_UNKNOWN_CREDENTIAL', '%s identifier does not exist: %s', Error);
 E('ERR_UNKNOWN_ENCODING', 'Unknown encoding: %s', TypeError);
-E('ERR_UNKNOWN_FILE_EXTENSION', (ext, path, suggestion) => {
-  let msg = `Unknown file extension "${ext}" for ${path}`;
-  if (suggestion) {
-    msg += `. ${suggestion}`;
-  }
-  return msg;
+E('ERR_UNKNOWN_FILE_EXTENSION', (ext, path) => {
+  return `Unknown file extension "${ext}" for ${path}`;
 }, TypeError);
 E('ERR_UNKNOWN_MODULE_FORMAT', 'Unknown module format: %s for URL %s',
   RangeError);
diff --git a/lib/internal/modules/esm/get_format.js b/lib/internal/modules/esm/get_format.js
index 59ab89f6f76377..dd5630aefed716 100644
--- a/lib/internal/modules/esm/get_format.js
+++ b/lib/internal/modules/esm/get_format.js
@@ -9,7 +9,6 @@ const {
   StringPrototypeCharCodeAt,
   StringPrototypeSlice,
 } = primordials;
-const { basename, relative } = require('path');
 const { getOptionValue } = require('internal/options');
 const {
   extensionFormatMap,
@@ -22,7 +21,7 @@ const experimentalNetworkImports =
 const defaultTypeFlag = getOptionValue('--experimental-default-type');
 // The next line is where we flip the default to ES modules someday.
 const defaultType = defaultTypeFlag === 'module' ? 'module' : 'commonjs';
-const { getPackageType, getPackageScopeConfig } = require('internal/modules/esm/resolve');
+const { getPackageType } = require('internal/modules/esm/resolve');
 const { fileURLToPath } = require('internal/url');
 const { ERR_UNKNOWN_FILE_EXTENSION } = require('internal/errors').codes;
 
@@ -112,17 +111,16 @@ function getFileProtocolModuleFormat(url, context, ignoreErrors) {
     if (defaultType === 'commonjs') { // Legacy behavior
       if (packageType === 'none' || packageType === 'commonjs') {
         return 'commonjs';
-      }
-      // If package type is `module`, fall through to the error case below
-    } else { // Else defaultType === 'module'
-      if (underNodeModules(url)) { // Exception for package scopes under `node_modules`
-        return 'commonjs';
-      }
-      if (packageType === 'none' || packageType === 'module') {
-        return getFormatOfExtensionlessFile(url);
-      } // Else packageType === 'commonjs'
+      } // Else packageType === 'module'
+      return getFormatOfExtensionlessFile(url);
+    } // Else defaultType === 'module'
+    if (underNodeModules(url)) { // Exception for package scopes under `node_modules`
       return 'commonjs';
     }
+    if (packageType === 'none' || packageType === 'module') {
+      return getFormatOfExtensionlessFile(url);
+    } // Else packageType === 'commonjs'
+    return 'commonjs';
   }
 
   const format = extensionFormatMap[ext];
@@ -131,17 +129,7 @@ function getFileProtocolModuleFormat(url, context, ignoreErrors) {
   // Explicit undefined return indicates load hook should rerun format check
   if (ignoreErrors) { return undefined; }
   const filepath = fileURLToPath(url);
-  let suggestion = '';
-  if (getPackageType(url) === 'module' && ext === '') {
-    const config = getPackageScopeConfig(url);
-    const fileBasename = basename(filepath);
-    const relativePath = StringPrototypeSlice(relative(config.pjsonPath, filepath), 1);
-    suggestion = 'Loading extensionless files is not supported inside of "type":"module" package.json contexts ' +
-      `without --experimental-default-type=module. The package.json file ${config.pjsonPath} caused this "type":"module" ` +
-      `context. Try changing ${filepath} to have a file extension. Note the "bin" field of package.json can point ` +
-      `to a file with an extension, for example {"type":"module","bin":{"${fileBasename}":"${relativePath}.js"}}`;
-  }
-  throw new ERR_UNKNOWN_FILE_EXTENSION(ext, filepath, suggestion);
+  throw new ERR_UNKNOWN_FILE_EXTENSION(ext, filepath);
 }
 
 /**
diff --git a/test/es-module/test-esm-extensionless-esm-and-wasm.mjs b/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
new file mode 100644
index 00000000000000..a57529f3c0a7b4
--- /dev/null
+++ b/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
@@ -0,0 +1,93 @@
+// Flags: --experimental-wasm-modules
+import { mustNotCall, spawnPromisified } from '../common/index.mjs';
+import * as fixtures from '../common/fixtures.mjs';
+import { describe, it } from 'node:test';
+import { match, ok, strictEqual } from 'node:assert';
+
+describe('extensionless ES modules within a "type": "module" package scope', { concurrency: true }, () => {
+  it('should run as the entry point', async () => {
+    const { code, signal, stdout, stderr } = await spawnPromisified(process.execPath, [
+      fixtures.path('es-modules/package-type-module/noext-esm'),
+    ]);
+
+    strictEqual(stderr, '');
+    strictEqual(stdout, 'executed\n');
+    strictEqual(code, 0);
+    strictEqual(signal, null);
+  });
+
+  it('should be importable', async () => {
+    const { default: defaultExport } =
+              await import(fixtures.fileURL('es-modules/package-type-module/noext-esm'));
+    strictEqual(defaultExport, 'module');
+  });
+});
+describe('extensionless Wasm modules within a "type": "module" package scope', { concurrency: true }, () => {
+  it('should run as the entry point', async () => {
+    const { code, signal, stdout, stderr } = await spawnPromisified(process.execPath, [
+      '--experimental-wasm-modules',
+      '--no-warnings',
+      fixtures.path('es-modules/package-type-module/noext-wasm'),
+    ]);
+
+    strictEqual(stderr, '');
+    strictEqual(stdout, 'executed\n');
+    strictEqual(code, 0);
+    strictEqual(signal, null);
+  });
+
+  it('should be importable', async () => {
+    const { add } = await import(fixtures.fileURL('es-modules/package-type-module/noext-wasm'));
+    strictEqual(add(1, 2), 3);
+  });
+});
+
+describe('extensionless ES modules within no package scope', { concurrency: true }, () => {
+  // This succeeds with `--experimental-default-type=module`
+  it('should error as the entry point', async () => {
+    const { code, signal, stdout, stderr } = await spawnPromisified(process.execPath, [
+      fixtures.path('es-modules/noext-esm'),
+    ]);
+
+    match(stderr, /SyntaxError/);
+    strictEqual(stdout, '');
+    strictEqual(code, 1);
+    strictEqual(signal, null);
+  });
+
+  // This succeeds with `--experimental-default-type=module`
+  it('should error on import', async () => {
+    try {
+      await import(fixtures.fileURL('es-modules/noext-esm'));
+      mustNotCall();
+    } catch (err) {
+      ok(err instanceof SyntaxError);
+    }
+  });
+});
+
+describe('extensionless Wasm within no package scope', { concurrency: true }, () => {
+  // This succeeds with `--experimental-default-type=module`
+  it('should error as the entry point', async () => {
+    const { code, signal, stdout, stderr } = await spawnPromisified(process.execPath, [
+      '--experimental-wasm-modules',
+      '--no-warnings',
+      fixtures.path('es-modules/noext-wasm'),
+    ]);
+
+    match(stderr, /SyntaxError/);
+    strictEqual(stdout, '');
+    strictEqual(code, 1);
+    strictEqual(signal, null);
+  });
+
+  // This succeeds with `--experimental-default-type=module`
+  it('should error on import', async () => {
+    try {
+      await import(fixtures.fileURL('es-modules/noext-wasm'));
+      mustNotCall();
+    } catch (err) {
+      ok(err instanceof SyntaxError);
+    }
+  });
+});
diff --git a/test/es-module/test-esm-unknown-or-no-extension.js b/test/es-module/test-esm-unknown-extension.js
similarity index 65%
rename from test/es-module/test-esm-unknown-or-no-extension.js
rename to test/es-module/test-esm-unknown-extension.js
index 83ebcc6267bfc3..dae9568c523fe5 100644
--- a/test/es-module/test-esm-unknown-or-no-extension.js
+++ b/test/es-module/test-esm-unknown-extension.js
@@ -7,14 +7,11 @@ const { execPath } = require('node:process');
 const { describe, it } = require('node:test');
 
 
-// In a "type": "module" package scope, files with unknown extensions or no
-// extensions should throw; both when used as a main entry point and also when
-// referenced via `import`.
-describe('ESM: extensionless and unknown specifiers', { concurrency: true }, () => {
+// In a "type": "module" package scope, files with unknown extensions should throw;
+// both when used as a main entry point and also when referenced via `import`.
+describe('ESM: unknown specifiers', { concurrency: true }, () => {
   for (
     const fixturePath of [
-      '/es-modules/package-type-module/noext-esm',
-      '/es-modules/package-type-module/imports-noext.mjs',
       '/es-modules/package-type-module/extension.unknown',
       '/es-modules/package-type-module/imports-unknownext.mjs',
     ]
@@ -27,10 +24,6 @@ describe('ESM: extensionless and unknown specifiers', { concurrency: true }, ()
       assert.strictEqual(signal, null);
       assert.strictEqual(stdout, '');
       assert.match(stderr, /ERR_UNKNOWN_FILE_EXTENSION/);
-      if (fixturePath.includes('noext')) {
-        // Check for explanation to users
-        assert.match(stderr, /extensionless/);
-      }
     });
   }
 });

From f2ae2d7e524f9e461cafdbb5c14a262fdc68d9b3 Mon Sep 17 00:00:00 2001
From: Geoffrey Booth <webadmin@geoffreybooth.com>
Date: Mon, 2 Oct 2023 14:12:22 -0700
Subject: [PATCH 2/5] Simplify error

---
 lib/internal/errors.js | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/lib/internal/errors.js b/lib/internal/errors.js
index 7111cf57f9c5d1..a4abc0f49c365d 100644
--- a/lib/internal/errors.js
+++ b/lib/internal/errors.js
@@ -1760,9 +1760,7 @@ E('ERR_UNHANDLED_ERROR',
 E('ERR_UNKNOWN_BUILTIN_MODULE', 'No such built-in module: %s', Error);
 E('ERR_UNKNOWN_CREDENTIAL', '%s identifier does not exist: %s', Error);
 E('ERR_UNKNOWN_ENCODING', 'Unknown encoding: %s', TypeError);
-E('ERR_UNKNOWN_FILE_EXTENSION', (ext, path) => {
-  return `Unknown file extension "${ext}" for ${path}`;
-}, TypeError);
+E('ERR_UNKNOWN_FILE_EXTENSION', 'Unknown file extension "%s" for %s', TypeError);
 E('ERR_UNKNOWN_MODULE_FORMAT', 'Unknown module format: %s for URL %s',
   RangeError);
 E('ERR_UNKNOWN_SIGNAL', 'Unknown signal: %s', TypeError);

From fd3537d821648831756b593f2fac0bb0ccc9e014 Mon Sep 17 00:00:00 2001
From: Geoffrey Booth <webadmin@geoffreybooth.com>
Date: Mon, 2 Oct 2023 17:56:53 -0700
Subject: [PATCH 3/5] Fix extensionless in module package under node_modules

---
 lib/internal/modules/esm/get_format.js             |  2 +-
 .../test-esm-extensionless-esm-and-wasm.mjs        |  6 ++++++
 .../test-esm-type-flag-package-scopes.mjs          | 14 ++++++++++----
 .../dep-with-package-json-type-module/noext-esm    |  2 ++
 .../dep-with-package-json-type-module/package.json |  8 ++++++++
 .../dep.js                                         |  0
 .../noext-cjs                                      |  0
 .../package.json                                   |  2 +-
 .../run.js                                         |  0
 9 files changed, 28 insertions(+), 6 deletions(-)
 create mode 100644 test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm
 create mode 100644 test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/package.json
 rename test/fixtures/es-modules/package-type-module/node_modules/{dep-with-package-json => dep-with-package-json-without-type}/dep.js (100%)
 rename test/fixtures/es-modules/package-type-module/node_modules/{dep-with-package-json => dep-with-package-json-without-type}/noext-cjs (100%)
 rename test/fixtures/es-modules/package-type-module/node_modules/{dep-with-package-json => dep-with-package-json-without-type}/package.json (56%)
 rename test/fixtures/es-modules/package-type-module/node_modules/{dep-with-package-json => dep-with-package-json-without-type}/run.js (100%)

diff --git a/lib/internal/modules/esm/get_format.js b/lib/internal/modules/esm/get_format.js
index dd5630aefed716..94435e0952c739 100644
--- a/lib/internal/modules/esm/get_format.js
+++ b/lib/internal/modules/esm/get_format.js
@@ -115,7 +115,7 @@ function getFileProtocolModuleFormat(url, context, ignoreErrors) {
       return getFormatOfExtensionlessFile(url);
     } // Else defaultType === 'module'
     if (underNodeModules(url)) { // Exception for package scopes under `node_modules`
-      return 'commonjs';
+      return packageType === 'module' ? 'module' : 'commonjs';
     }
     if (packageType === 'none' || packageType === 'module') {
       return getFormatOfExtensionlessFile(url);
diff --git a/test/es-module/test-esm-extensionless-esm-and-wasm.mjs b/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
index a57529f3c0a7b4..d5075c5397b0ff 100644
--- a/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
+++ b/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
@@ -21,6 +21,12 @@ describe('extensionless ES modules within a "type": "module" package scope', { c
               await import(fixtures.fileURL('es-modules/package-type-module/noext-esm'));
     strictEqual(defaultExport, 'module');
   });
+
+  it('should be importable from a module scope under node_modules', async () => {
+    const { default: defaultExport } =
+              await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm'));
+    strictEqual(defaultExport, 'module');
+  });
 });
 describe('extensionless Wasm modules within a "type": "module" package scope', { concurrency: true }, () => {
   it('should run as the entry point', async () => {
diff --git a/test/es-module/test-esm-type-flag-package-scopes.mjs b/test/es-module/test-esm-type-flag-package-scopes.mjs
index 6b16e8a3ae223b..0df286f95ad0f5 100644
--- a/test/es-module/test-esm-type-flag-package-scopes.mjs
+++ b/test/es-module/test-esm-type-flag-package-scopes.mjs
@@ -24,6 +24,12 @@ describe('the type flag should change the interpretation of certain files within
              strictEqual(defaultExport, 'module');
            });
 
+           it('should import an extensionless JavaScript file within a "type": "module" scope under node_modules', async () => {
+            const { default: defaultExport } =
+                      await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm'));
+            strictEqual(defaultExport, 'module');
+          });
+
            it('should run as Wasm an extensionless Wasm file within a "type": "module" scope', async () => {
              const { code, signal, stdout, stderr } = await spawnPromisified(process.execPath, [
                '--experimental-default-type=module',
@@ -112,7 +118,7 @@ describe(`the type flag should NOT change the interpretation of certain files wi
      async () => {
        const { code, signal, stdout, stderr } = await spawnPromisified(process.execPath, [
          '--experimental-default-type=module',
-         fixtures.path('es-modules/package-type-module/node_modules/dep-with-package-json/run.js'),
+         fixtures.path('es-modules/package-type-module/node_modules/dep-with-package-json-without-type/run.js'),
        ]);
 
        strictEqual(stderr, '');
@@ -124,7 +130,7 @@ describe(`the type flag should NOT change the interpretation of certain files wi
   it(`should import as CommonJS a .js file within a package scope that has no defined "type" and is under
   node_modules`, async () => {
     const { default: defaultExport } =
-      await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json/run.js'));
+      await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-without-type/run.js'));
     strictEqual(defaultExport, 42);
   });
 
@@ -132,7 +138,7 @@ describe(`the type flag should NOT change the interpretation of certain files wi
   under node_modules`, async () => {
     const { code, signal, stdout, stderr } = await spawnPromisified(process.execPath, [
       '--experimental-default-type=module',
-      fixtures.path('es-modules/package-type-module/node_modules/dep-with-package-json/noext-cjs'),
+      fixtures.path('es-modules/package-type-module/node_modules/dep-with-package-json-without-type/noext-cjs'),
     ]);
 
     strictEqual(stderr, '');
@@ -144,7 +150,7 @@ describe(`the type flag should NOT change the interpretation of certain files wi
   it(`should import as CommonJS an extensionless JavaScript file within a package scope that has no defined "type" and
   is under node_modules`, async () => {
     const { default: defaultExport } =
-      await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json/noext-cjs'));
+      await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-without-type/noext-cjs'));
     strictEqual(defaultExport, 42);
   });
 });
diff --git a/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm
new file mode 100644
index 00000000000000..251d6e538a1fcf
--- /dev/null
+++ b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm
@@ -0,0 +1,2 @@
+export default 'module';
+console.log('executed');
diff --git a/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/package.json b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/package.json
new file mode 100644
index 00000000000000..8d155c74efe78a
--- /dev/null
+++ b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "dep-with-package-json-type-module",
+  "type": "module",
+  "version": "1.0.0",
+  "exports": {
+    "./*": "./*"
+  }
+}
diff --git a/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json/dep.js b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-without-type/dep.js
similarity index 100%
rename from test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json/dep.js
rename to test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-without-type/dep.js
diff --git a/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json/noext-cjs b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-without-type/noext-cjs
similarity index 100%
rename from test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json/noext-cjs
rename to test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-without-type/noext-cjs
diff --git a/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json/package.json b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-without-type/package.json
similarity index 56%
rename from test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json/package.json
rename to test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-without-type/package.json
index 5ee78b14c414b2..1b83367ebe3f5f 100644
--- a/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json/package.json
+++ b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-without-type/package.json
@@ -1,5 +1,5 @@
 {
-  "name": "dep-with-package-json",
+  "name": "dep-with-package-json-without-type",
   "version": "1.0.0",
   "exports": {
     "./*": "./*"
diff --git a/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json/run.js b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-without-type/run.js
similarity index 100%
rename from test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json/run.js
rename to test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-without-type/run.js

From 2041ddd557367b910acb45eea2b9e178a9805182 Mon Sep 17 00:00:00 2001
From: Geoffrey Booth <webadmin@geoffreybooth.com>
Date: Mon, 2 Oct 2023 18:18:54 -0700
Subject: [PATCH 4/5] Wasm too

---
 lib/internal/modules/esm/get_format.js           |   2 +-
 .../test-esm-extensionless-esm-and-wasm.mjs      |   5 +++++
 .../test-esm-type-flag-package-scopes.mjs        |   5 +++++
 .../dep-with-package-json-type-module/noext-wasm | Bin 0 -> 136 bytes
 .../wasm-dep.mjs                                 |  15 +++++++++++++++
 5 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-wasm
 create mode 100644 test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/wasm-dep.mjs

diff --git a/lib/internal/modules/esm/get_format.js b/lib/internal/modules/esm/get_format.js
index 94435e0952c739..56d002ca0883ad 100644
--- a/lib/internal/modules/esm/get_format.js
+++ b/lib/internal/modules/esm/get_format.js
@@ -115,7 +115,7 @@ function getFileProtocolModuleFormat(url, context, ignoreErrors) {
       return getFormatOfExtensionlessFile(url);
     } // Else defaultType === 'module'
     if (underNodeModules(url)) { // Exception for package scopes under `node_modules`
-      return packageType === 'module' ? 'module' : 'commonjs';
+      return packageType === 'module' ? getFormatOfExtensionlessFile(url) : 'commonjs';
     }
     if (packageType === 'none' || packageType === 'module') {
       return getFormatOfExtensionlessFile(url);
diff --git a/test/es-module/test-esm-extensionless-esm-and-wasm.mjs b/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
index d5075c5397b0ff..df8f8a6fe9c780 100644
--- a/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
+++ b/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
@@ -46,6 +46,11 @@ describe('extensionless Wasm modules within a "type": "module" package scope', {
     const { add } = await import(fixtures.fileURL('es-modules/package-type-module/noext-wasm'));
     strictEqual(add(1, 2), 3);
   });
+
+  it('should be importable from a module scope under node_modules', async () => {
+    const { add } = await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-wasm'));
+    strictEqual(add(1, 2), 3);
+  });
 });
 
 describe('extensionless ES modules within no package scope', { concurrency: true }, () => {
diff --git a/test/es-module/test-esm-type-flag-package-scopes.mjs b/test/es-module/test-esm-type-flag-package-scopes.mjs
index 0df286f95ad0f5..bb1d52ae57ef1a 100644
--- a/test/es-module/test-esm-type-flag-package-scopes.mjs
+++ b/test/es-module/test-esm-type-flag-package-scopes.mjs
@@ -48,6 +48,11 @@ describe('the type flag should change the interpretation of certain files within
              const { add } = await import(fixtures.fileURL('es-modules/package-type-module/noext-wasm'));
              strictEqual(add(1, 2), 3);
            });
+
+           it('should import an extensionless Wasm file within a "type": "module" scope under node_modules', async () => {
+            const { add } = await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-wasm'));
+            strictEqual(add(1, 2), 3);
+          });
          });
 
 describe(`the type flag should change the interpretation of certain files within a package scope that lacks a
diff --git a/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-wasm b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-wasm
new file mode 100644
index 0000000000000000000000000000000000000000..9e035904b2e4d0a30ce5a63bcf05cc3a2c8449db
GIT binary patch
literal 136
zcmZ9COA5k35Jam#kl=s>MAx~130^|TEhaEo*f23T0he=in=IYDDqa=lk_iA^G=gdb
zBG>AL9Q@$(Fn;}VPs=uBD{AGr0)Mu(GOe%O7ZMd>X|61DN|4~3^7j7hOM<q<r<*7`
N3JrSnWJh+e@B?GW9Ay9i

literal 0
HcmV?d00001

diff --git a/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/wasm-dep.mjs b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/wasm-dep.mjs
new file mode 100644
index 00000000000000..a0e28aa17b6bd9
--- /dev/null
+++ b/test/fixtures/es-modules/package-type-module/node_modules/dep-with-package-json-type-module/wasm-dep.mjs
@@ -0,0 +1,15 @@
+import { strictEqual } from 'assert';
+
+export function jsFn () {
+  state = 'WASM JS Function Executed';
+  return 42;
+}
+
+export let state = 'JS Function Executed';
+
+export function jsInitFn () {
+  strictEqual(state, 'JS Function Executed');
+  state = 'WASM Start Executed';
+}
+
+console.log('executed');

From bd374f885636a233a6b48513db14581cb6dcebf8 Mon Sep 17 00:00:00 2001
From: Geoffrey Booth <webadmin@geoffreybooth.com>
Date: Mon, 2 Oct 2023 18:24:37 -0700
Subject: [PATCH 5/5] Lint

---
 .../test-esm-extensionless-esm-and-wasm.mjs   |  6 ++--
 .../test-esm-type-flag-package-scopes.mjs     | 28 +++++++++++--------
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/test/es-module/test-esm-extensionless-esm-and-wasm.mjs b/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
index df8f8a6fe9c780..db20bc047feec1 100644
--- a/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
+++ b/test/es-module/test-esm-extensionless-esm-and-wasm.mjs
@@ -24,7 +24,8 @@ describe('extensionless ES modules within a "type": "module" package scope', { c
 
   it('should be importable from a module scope under node_modules', async () => {
     const { default: defaultExport } =
-              await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm'));
+      await import(fixtures.fileURL(
+        'es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm'));
     strictEqual(defaultExport, 'module');
   });
 });
@@ -48,7 +49,8 @@ describe('extensionless Wasm modules within a "type": "module" package scope', {
   });
 
   it('should be importable from a module scope under node_modules', async () => {
-    const { add } = await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-wasm'));
+    const { add } = await import(fixtures.fileURL(
+      'es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-wasm'));
     strictEqual(add(1, 2), 3);
   });
 });
diff --git a/test/es-module/test-esm-type-flag-package-scopes.mjs b/test/es-module/test-esm-type-flag-package-scopes.mjs
index bb1d52ae57ef1a..bf9d7d7ca4944c 100644
--- a/test/es-module/test-esm-type-flag-package-scopes.mjs
+++ b/test/es-module/test-esm-type-flag-package-scopes.mjs
@@ -24,11 +24,13 @@ describe('the type flag should change the interpretation of certain files within
              strictEqual(defaultExport, 'module');
            });
 
-           it('should import an extensionless JavaScript file within a "type": "module" scope under node_modules', async () => {
-            const { default: defaultExport } =
-                      await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm'));
-            strictEqual(defaultExport, 'module');
-          });
+           it('should import an extensionless JavaScript file within a "type": "module" scope under node_modules',
+              async () => {
+                const { default: defaultExport } =
+                await import(fixtures.fileURL(
+                  'es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-esm'));
+                strictEqual(defaultExport, 'module');
+              });
 
            it('should run as Wasm an extensionless Wasm file within a "type": "module" scope', async () => {
              const { code, signal, stdout, stderr } = await spawnPromisified(process.execPath, [
@@ -49,10 +51,12 @@ describe('the type flag should change the interpretation of certain files within
              strictEqual(add(1, 2), 3);
            });
 
-           it('should import an extensionless Wasm file within a "type": "module" scope under node_modules', async () => {
-            const { add } = await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-wasm'));
-            strictEqual(add(1, 2), 3);
-          });
+           it('should import an extensionless Wasm file within a "type": "module" scope under node_modules',
+              async () => {
+                const { add } = await import(fixtures.fileURL(
+                  'es-modules/package-type-module/node_modules/dep-with-package-json-type-module/noext-wasm'));
+                strictEqual(add(1, 2), 3);
+              });
          });
 
 describe(`the type flag should change the interpretation of certain files within a package scope that lacks a
@@ -135,7 +139,8 @@ describe(`the type flag should NOT change the interpretation of certain files wi
   it(`should import as CommonJS a .js file within a package scope that has no defined "type" and is under
   node_modules`, async () => {
     const { default: defaultExport } =
-      await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-without-type/run.js'));
+      await import(fixtures.fileURL(
+        'es-modules/package-type-module/node_modules/dep-with-package-json-without-type/run.js'));
     strictEqual(defaultExport, 42);
   });
 
@@ -155,7 +160,8 @@ describe(`the type flag should NOT change the interpretation of certain files wi
   it(`should import as CommonJS an extensionless JavaScript file within a package scope that has no defined "type" and
   is under node_modules`, async () => {
     const { default: defaultExport } =
-      await import(fixtures.fileURL('es-modules/package-type-module/node_modules/dep-with-package-json-without-type/noext-cjs'));
+      await import(fixtures.fileURL(
+        'es-modules/package-type-module/node_modules/dep-with-package-json-without-type/noext-cjs'));
     strictEqual(defaultExport, 42);
   });
 });