LibJS: Make Object::to_string() call the "toString" property if present

2 files changed, 9 insertions, 1 deletions

diff --git a/Libraries/LibJS/Runtime/Object.cpp b/Libraries/LibJS/Runtime/Object.cpp
index c29c7f85d1..6598a3af76 100644
--- a/Libraries/LibJS/Runtime/Object.cpp
+++ b/Libraries/LibJS/Runtime/Object.cpp
@@ -205,6 +205,14 @@ Value Object::to_primitive(PreferredType preferred_type) const
 
 Value Object::to_string() const
 {
+    auto to_string_property = get("toString");
+    if (to_string_property.has_value()
+        && to_string_property.value().is_object()
+        && to_string_property.value().as_object().is_function()) {
+        auto& to_string_function = static_cast<Function&>(to_string_property.value().as_object());
+        return const_cast<Object*>(this)->interpreter().call(&to_string_function, const_cast<Object*>(this));
+    }
     return js_string(heap(), String::format("[object %s]", class_name()));
 }
+
 }
diff --git a/Libraries/LibJS/Runtime/ObjectPrototype.cpp b/Libraries/LibJS/Runtime/ObjectPrototype.cpp
index 92e06048b2..c70c590253 100644
--- a/Libraries/LibJS/Runtime/ObjectPrototype.cpp
+++ b/Libraries/LibJS/Runtime/ObjectPrototype.cpp
@@ -61,7 +61,7 @@ Value ObjectPrototype::to_string(Interpreter& interpreter)
     auto* this_object = interpreter.this_value().to_object(interpreter.heap());
     if (!this_object)
         return {};
-    return Value(this_object->to_string());
+    return js_string(interpreter, String::format("[object %s]", this_object->class_name()));
 }
 
 Value ObjectPrototype::value_of(Interpreter& interpreter)