LibJS: Convert StringIterator.prototype to be a PrototypeObject

Userland/Libraries/LibJS/Runtime/StringIteratorPrototype.cpp

@@ -9,13 +9,12 @@
 #include <LibJS/Runtime/Error.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/IteratorOperations.h>
-#include <LibJS/Runtime/StringIterator.h>
 #include <LibJS/Runtime/StringIteratorPrototype.h>
 
 namespace JS {
 
 StringIteratorPrototype::StringIteratorPrototype(GlobalObject& global_object)
-    : Object(*global_object.iterator_prototype())
+    : PrototypeObject(*global_object.iterator_prototype())
 {
 }
 
@@ -36,21 +35,17 @@ StringIteratorPrototype::~StringIteratorPrototype()
 // 22.1.5.1.1 %StringIteratorPrototype%.next ( ), https://tc39.es/ecma262/#sec-%stringiteratorprototype%.next
 JS_DEFINE_NATIVE_FUNCTION(StringIteratorPrototype::next)
 {
-    auto this_value = vm.this_value(global_object);
-    if (!this_value.is_object() || !is<StringIterator>(this_value.as_object())) {
-        vm.throw_exception<TypeError>(global_object, ErrorType::NotAnObjectOfType, "String Iterator");
+    auto* iterator = typed_this_value(global_object);
+    if (vm.exception())
         return {};
-    }
 
-    auto& this_object = this_value.as_object();
-    auto& iterator = static_cast<StringIterator&>(this_object);
-    if (iterator.done())
+    if (iterator->done())
         return create_iterator_result_object(global_object, js_undefined(), true);
 
-    auto& utf8_iterator = iterator.iterator();
+    auto& utf8_iterator = iterator->iterator();
 
     if (utf8_iterator.done()) {
-        iterator.m_done = true;
+        iterator->m_done = true;
         return create_iterator_result_object(global_object, js_undefined(), true);
     }
 

Userland/Libraries/LibJS/Runtime/StringIteratorPrototype.h

@@ -7,11 +7,13 @@
 #pragma once
 
 #include <LibJS/Runtime/Object.h>
+#include <LibJS/Runtime/PrototypeObject.h>
+#include <LibJS/Runtime/StringIterator.h>
 
 namespace JS {
 
-class StringIteratorPrototype final : public Object {
-    JS_OBJECT(StringIteratorPrototype, Object)
+class StringIteratorPrototype final : public PrototypeObject<StringIteratorPrototype, StringIterator> {
+    JS_PROTOTYPE_OBJECT(StringIteratorPrototype, StringIterator, StringIterator);
 
 public:
     StringIteratorPrototype(GlobalObject&);