esm: support top-level Wasm without package type

PR-URL: https://github.com/nodejs/node/pull/57610
Reviewed-By: Jordan Harband <ljharb@gmail.com>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

doc/api/cli.md

@@ -33,7 +33,8 @@ If a file is found, its path will be passed to the
 
 * The program was started with a command-line flag that forces the entry
   point to be loaded with ECMAScript module loader, such as `--import`.
-* The file has an `.mjs` extension.
+* The file has an `.mjs` or `.wasm` (with `--experimental-wasm-modules`)
+  extension.
 * The file does not have a `.cjs` extension, and the nearest parent
   `package.json` file contains a top-level [`"type"`][] field with a value of
   `"module"`.

lib/internal/modules/run_main.js

@@ -62,6 +62,7 @@ function shouldUseESMLoader(mainPath) {
 
   // Determine the module format of the entry point.
   if (mainPath && StringPrototypeEndsWith(mainPath, '.mjs')) { return true; }
+  if (mainPath && StringPrototypeEndsWith(mainPath, '.wasm')) { return true; }
   if (!mainPath || StringPrototypeEndsWith(mainPath, '.cjs')) { return false; }
 
   if (getOptionValue('--experimental-strip-types')) {

test/es-module/test-esm-wasm.mjs

@@ -91,6 +91,18 @@ describe('ESM: WASM modules', { concurrency: !process.env.TEST_PARALLEL }, () =>
     match(stderr, /WebAssembly/);
   });
 
+  it('should support top-level execution', async () => {
+    const { code, stderr, stdout } = await spawnPromisified(execPath, [
+      '--no-warnings',
+      '--experimental-wasm-modules',
+      fixtures.path('es-modules/top-level-wasm.wasm'),
+    ]);
+
+    strictEqual(stderr, '');
+    strictEqual(stdout, '[Object: null prototype] { prop: \'hello world\' }\n');
+    strictEqual(code, 0);
+  });
+
   it('should support static source phase imports', async () => {
     const { code, stderr, stdout } = await spawnPromisified(execPath, [
       '--no-warnings',

test/fixtures/es-modules/wasm-function.js

@@ -0,0 +1,11 @@
+export function call1 (func, thisObj, arg0) {
+  return func.call(thisObj, arg0);
+}
+
+export function call2 (func, thisObj, arg0, arg1) {
+  return func.call(thisObj, arg0, arg1);
+}
+
+export function call3 (func, thisObj, arg0, arg1, arg2) {
+  return func.call(thisObj, arg0, arg1, arg2);
+}

test/fixtures/es-modules/wasm-object.js

@@ -0,0 +1,3 @@
+export const { get: getProperty, set: setProperty } = Reflect;
+export const { create } = Object;
+export const global = globalThis;

test/fixtures/es-modules/wasm-string-constants.js

@@ -0,0 +1,6 @@
+const console = 'console';
+const hello_world = 'hello world';
+const log = 'log';
+const prop = 'prop';
+
+export { console, hello_world as 'hello world', log, prop }