respect mainScriptUrlOrBlob for esm targets

src/lib/libpthread.js

@@ -413,49 +413,44 @@ var LibraryPThread = {
 
     // Creates a new web Worker and places it in the unused worker pool to wait for its use.
     allocateUnusedWorker() {
-      var worker;
+      var workerUrl, workerSource;
 #if EXPORT_ES6
-      // If we're using module output, use bundler-friendly pattern.
-#if PTHREADS_DEBUG
-      dbg(`Allocating a new web worker from ${import.meta.url}`);
-#endif
-#if TRUSTED_TYPES
-      // Use Trusted Types compatible wrappers.
-      if (typeof trustedTypes != 'undefined' && trustedTypes.createPolicy) {
-        var p = trustedTypes.createPolicy('emscripten#workerPolicy1', { createScriptURL: (ignored) => import.meta.url });
-        worker = new Worker(p.createScriptURL('ignored'), {{{ pthreadWorkerOptions }}});
-      } else
+      workerSource = import.meta.url;
+#else
+      workerUrl = workerSource = _scriptName;
 #endif
-      // We need to generate the URL with import.meta.url as the base URL of the JS file
-      // instead of just using new URL(import.meta.url) because bundler's only recognize
-      // the first case in their bundling step. The latter ends up producing an invalid
-      // URL to import from the server (e.g., for webpack the file:// path).
-      // See https://github.com/webpack/webpack/issues/12638
-      worker = new Worker(new URL('{{{ TARGET_JS_NAME }}}', import.meta.url), {{{ pthreadWorkerOptions }}});
-#else // EXPORT_ES6
-      var pthreadMainJs = _scriptName;
 #if expectToReceiveOnModule('mainScriptUrlOrBlob')
-      // We can't use makeModuleReceiveWithVar here since we want to also
-      // call URL.createObjectURL on the mainScriptUrlOrBlob.
       if (Module['mainScriptUrlOrBlob']) {
-        pthreadMainJs = Module['mainScriptUrlOrBlob'];
-        if (typeof pthreadMainJs != 'string') {
-          pthreadMainJs = URL.createObjectURL(pthreadMainJs);
+        // We can't use makeModuleReceiveWithVar here since we want to also
+        // call URL.createObjectURL on the mainScriptUrlOrBlob.
+        workerSource = workerUrl = Module['mainScriptUrlOrBlob'];
+        if (typeof workerUrl != 'string') {
+          workerSource = workerUrl = URL.createObjectURL(workerUrl);
         }
       }
 #endif
 #if PTHREADS_DEBUG
-      dbg(`Allocating a new web worker from ${pthreadMainJs}`);
+      dbg(`Allocating a new web worker from ${workerSource}`);
 #endif
 #if TRUSTED_TYPES
       // Use Trusted Types compatible wrappers.
       if (typeof trustedTypes != 'undefined' && trustedTypes.createPolicy) {
-        var p = trustedTypes.createPolicy('emscripten#workerPolicy2', { createScriptURL: (ignored) => pthreadMainJs });
-        worker = new Worker(p.createScriptURL('ignored'), {{{ pthreadWorkerOptions }}});
+        var p = trustedTypes.createPolicy('emscripten#workerPolicy2', { createScriptURL: (ignored) => workerSource });
+        workerUrl = p.createScriptURL('ignored');
+      }
+#endif
+      var worker;
+#if EXPORT_ES6
+      if (!workerUrl) {
+      // We need to generate the URL with import.meta.url as the base URL of the JS file
+      // instead of just using new URL(import.meta.url) because bundler's only recognize
+      // the first case in their bundling step. The latter ends up producing an invalid
+      // URL to import from the server (e.g., for webpack the file:// path).
+      // See https://github.com/webpack/webpack/issues/12638
+        worker = new Worker(new URL("{{{ TARGET_JS_NAME }}}", import.meta.url), {{{ pthreadWorkerOptions }}});
       } else
 #endif
-      worker = new Worker(pthreadMainJs, {{{ pthreadWorkerOptions }}});
-#endif // EXPORT_ES6
+      worker = new Worker(workerUrl, {{{ pthreadWorkerOptions }}});
 #if ASSERTIONS
       worker.workerID = PThread.nextWorkerID++;
 #endif