test: deflake test-esm-loader-resolve-type

test/fixtures/es-module-loaders/hook-resolve-type-loader.mjs

@@ -1,17 +1,24 @@
-/** @type {MessagePort} */
-let port;
-export function initialize(data) {
-  port = data.port;
+/** @type {Uint8Array} */
+let data;
+/** @type {number} */
+let ESM_MODULE_INDEX;
+/** @type {number} */
+let CJS_MODULE_INDEX;
+
+export function initialize({ sab, ESM_MODULE_INDEX:e, CJS_MODULE_INDEX:c }) {
+  data = new Uint8Array(sab);
+  ESM_MODULE_INDEX = e;
+  CJS_MODULE_INDEX = c;
 }
 
 export async function resolve(specifier, context, next) {
   const nextResult = await next(specifier, context);
   const { format } = nextResult;
 
   if (format === 'module' || specifier.endsWith('.mjs')) {
-    port.postMessage({ type: 'module' });
+    Atomics.add(data, ESM_MODULE_INDEX, 1);
   } else if (format == null || format === 'commonjs') {
-    port.postMessage({ type: 'commonjs' });
+    Atomics.add(data, CJS_MODULE_INDEX, 1);
   }
 
   return nextResult;

test/fixtures/es-module-loaders/hook-resolve-type.mjs

@@ -1,30 +1,18 @@
 import * as fixtures from '../../common/fixtures.mjs';
 import { register } from 'node:module';
-import { MessageChannel } from 'node:worker_threads';
 
-let importedESM = 0;
-let importedCJS = 0;
+const sab = new SharedArrayBuffer(2);
+const data = new Uint8Array(sab);
+
+const ESM_MODULE_INDEX = 0
+const CJS_MODULE_INDEX = 1
+
 export function getModuleTypeStats() {
+  const importedESM = Atomics.load(data, ESM_MODULE_INDEX);
+  const importedCJS = Atomics.load(data, CJS_MODULE_INDEX);
   return { importedESM, importedCJS };
-};
-
-const { port1, port2 } = new MessageChannel();
+}
 
 register(fixtures.fileURL('es-module-loaders/hook-resolve-type-loader.mjs'), {
-  data: { port: port2 },
-  transferList: [port2],
+  data: { sab, ESM_MODULE_INDEX, CJS_MODULE_INDEX },
 });
-
-port1.on('message', ({ type }) => {
-  switch (type) {
-    case 'module':
-      importedESM++;
-      break;
-    case 'commonjs':
-      importedCJS++;
-      break;
-  }
-});
-
-port1.unref();
-port2.unref();