LibJS: Add spec comments to ProxyConstructor

Userland/Libraries/LibJS/Runtime/ProxyConstructor.cpp

@@ -17,10 +17,24 @@ namespace JS {
 static ThrowCompletionOr<ProxyObject*> proxy_create(VM& vm, Value target, Value handler)
 {
  auto& realm = *vm.current_realm();
+
+ // 1. If target is not an Object, throw a TypeError exception.
  if (!target.is_object())
  return vm.throw_completion<TypeError>(ErrorType::ProxyConstructorBadType, "target", TRY_OR_THROW_OOM(vm, target.to_string_without_side_effects()));
+
+ // 2. If handler is not an Object, throw a TypeError exception.
  if (!handler.is_object())
  return vm.throw_completion<TypeError>(ErrorType::ProxyConstructorBadType, "handler", TRY_OR_THROW_OOM(vm, handler.to_string_without_side_effects()));
+
+ // 3. Let P be MakeBasicObject(« [[ProxyHandler]], [[ProxyTarget]] »).
+ // 4. Set P's essential internal methods, except for [[Call]] and [[Construct]], to the definitions specified in 10.5.
+ // 5. IsCallable(target) is true, then
+ // a. Set P.[[Call]] as specified in 10.5.12.
+ // b. If IsConstructor(target) is true, then
+ // i. Set P.[[Construct]] as specified in 10.5.13.
+ // 6. Set P.[[ProxyTarget]] to target.
+ // 7. Set P.[[ProxyHandler]] to handler.
+ // 8. Return P.
  return ProxyObject::create(realm, target.as_object(), handler.as_object()).ptr();
 }
 
@@ -45,23 +59,31 @@ ThrowCompletionOr<void> ProxyConstructor::initialize(Realm& realm)
 ThrowCompletionOr<Value> ProxyConstructor::call()
 {
  auto& vm = this->vm();
+
+ // 1. If NewTarget is undefined, throw a TypeError exception.
  return vm.throw_completion<TypeError>(ErrorType::ConstructorWithoutNew, vm.names.Proxy);
 }
 
 // 28.2.1.1 Proxy ( target, handler ), https://tc39.es/ecma262/#sec-proxy-target-handler
 ThrowCompletionOr<NonnullGCPtr<Object>> ProxyConstructor::construct(FunctionObject&)
 {
  auto& vm = this->vm();
- return *TRY(proxy_create(vm, vm.argument(0), vm.argument(1)));
+ auto target = vm.argument(0);
+ auto handler = vm.argument(1);
+
+ // 2. Return ? ProxyCreate(target, handler).
+ return *TRY(proxy_create(vm, target, handler));
 }
 
 // 28.2.2.1 Proxy.revocable ( target, handler ), https://tc39.es/ecma262/#sec-proxy.revocable
 JS_DEFINE_NATIVE_FUNCTION(ProxyConstructor::revocable)
 {
  auto& realm = *vm.current_realm();
+ auto target = vm.argument(0);
+ auto handler = vm.argument(1);
 
  // 1. Let p be ? ProxyCreate(target, handler).
- auto* proxy = TRY(proxy_create(vm, vm.argument(0), vm.argument(1)));
+ auto* proxy = TRY(proxy_create(vm, target, handler));
 
  // 2. Let revokerClosure be a new Abstract Closure with no parameters that captures nothing and performs the following steps when called:
  auto revoker_closure = [proxy_handle = make_handle(proxy)](auto&) -> ThrowCompletionOr<Value> {