LibJS: Don't define the "prototype" property for arrow functions

2 files changed, 6 insertions, 1 deletions

diff --git a/Libraries/LibJS/Runtime/ScriptFunction.cpp b/Libraries/LibJS/Runtime/ScriptFunction.cpp
index 5d0857823f..5828bcdde3 100644
--- a/Libraries/LibJS/Runtime/ScriptFunction.cpp
+++ b/Libraries/LibJS/Runtime/ScriptFunction.cpp
@@ -61,7 +61,8 @@ ScriptFunction::ScriptFunction(const FlyString& name, const Statement& body, Vec
     , m_function_length(m_function_length)
     , m_is_arrow_function(is_arrow_function)
 {
-    define_property("prototype", Object::create_empty(interpreter(), interpreter().global_object()), 0);
+    if (!is_arrow_function)
+        define_property("prototype", Object::create_empty(interpreter(), interpreter().global_object()), 0);
     define_native_property("length", length_getter, nullptr, Attribute::Configurable);
     define_native_property("name", name_getter, nullptr, Attribute::Configurable);
 }
diff --git a/Libraries/LibJS/Tests/arrow-functions.js b/Libraries/LibJS/Tests/arrow-functions.js
index d34a7836f2..e224415ded 100644
--- a/Libraries/LibJS/Tests/arrow-functions.js
+++ b/Libraries/LibJS/Tests/arrow-functions.js
@@ -77,6 +77,10 @@ try {
     assert(foobar.x.y() === foobar);
     assert(foobar.x.z() === foobar.x);
 
+    var Baz = () => {};
+
+    assert(Baz.prototype === undefined);
+
     (() => {
         "use strict";
         assert(isStrictMode());