LibJS: Parse async generator functions

Author: https://github.com/davidot
Commit: https://github.com/SerenityOS/serenity/commit/0982a73d1d8
Pull-request: https://github.com/SerenityOS/serenity/pull/10926
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibJS/Runtime/AsyncGeneratorFunctionConstructor.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2021, David Tuin <davidot@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibJS/Runtime/NativeFunction.h>
+
+namespace JS {
+
+class AsyncGeneratorFunctionConstructor final : public NativeFunction {
+    JS_OBJECT(AsyncGeneratorFunctionConstructor, NativeFunction);
+
+public:
+    explicit AsyncGeneratorFunctionConstructor(GlobalObject&);
+    virtual void initialize(GlobalObject&) override;
+    virtual ~AsyncGeneratorFunctionConstructor() override = default;
+
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<Object*> construct(FunctionObject& new_target) override;
+
+private:
+    virtual bool has_constructor() const override { return true; }
+};
+
+}