diff --git a/test/test_other.py b/test/test_other.py
index 4dabc8ecb3524..79098a8b03068 100644
--- a/test/test_other.py
+++ b/test/test_other.py
@@ -407,7 +407,8 @@ def test_export_es6_allows_export_in_post_js(self):
   @parameterized({
     '': ([],),
     # load a worker before startup to check ES6 modules there as well
-    'pthreads': (['-pthread', '-sPTHREAD_POOL_SIZE=1'],),
+    # pass -O2 to ensure the worker JS file is minified with Acorn
+    'pthreads': (['-O2', '-pthread', '-sPTHREAD_POOL_SIZE=1'],),
   })
   def test_export_es6(self, args, package_json):
     self.run_process([EMCC, test_file('hello_world.c'), '-sEXPORT_ES6',
diff --git a/tools/acorn-optimizer.mjs b/tools/acorn-optimizer.mjs
index c62e29f066665..f877761d636eb 100755
--- a/tools/acorn-optimizer.mjs
+++ b/tools/acorn-optimizer.mjs
@@ -2029,6 +2029,7 @@ try {
     preserveParens: closureFriendly,
     onComment: closureFriendly ? sourceComments : undefined,
     sourceType: exportES6 ? 'module' : 'script',
+    allowAwaitOutsideFunction: true,
   });
 } catch (err) {
   err.message += (() => {