Mirror API for IsAsyncFunction

src/runtime/runtime-function.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/accessors.h"
 #include "src/arguments.h"
 #include "src/compiler.h"
 #include "src/frames-inl.h"
@@ skipping 274 matching lines @@
 RUNTIME_FUNCTION(Runtime_FunctionToString) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(JSReceiver, function, 0);
   return function->IsJSBoundFunction()
              ? *JSBoundFunction::ToString(
                    Handle<JSBoundFunction>::cast(function))
              : *JSFunction::ToString(Handle<JSFunction>::cast(function));
 }
 
+RUNTIME_FUNCTION(Runtime_FunctionIsAsyncFunction) {
+  SealHandleScope shs(isolate);
+  DCHECK_EQ(1, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, function, 0);
+  bool is_async = false;
+  if (function->IsFunction()) {
+    is_async = Handle<JSFunction>::cast(function)->shared()->is_async();
+  }
+  return isolate->heap()->ToBoolean(is_async);
+}
+
 }  // namespace internal
 }  // namespace v8