LibJS: Add spec comments to ObjectPrototype

1 files changed, 149 insertions, 70 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/ObjectPrototype.cpp b/Userland/Libraries/LibJS/Runtime/ObjectPrototype.cpp
index 7c13b1a583..addd958b37 100644
--- a/Userland/Libraries/LibJS/Runtime/ObjectPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/ObjectPrototype.cpp
@@ -60,11 +60,74 @@ ThrowCompletionOr<bool> ObjectPrototype::internal_set_prototype_of(Object* proto
 // 20.1.3.2 Object.prototype.hasOwnProperty ( V ), https://tc39.es/ecma262/#sec-object.prototype.hasownproperty
 JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::has_own_property)
 {
+    // 1. Let P be ? ToPropertyKey(V).
     auto property_key = TRY(vm.argument(0).to_property_key(vm));
+
+    // 2. Let O be ? ToObject(this value).
     auto this_object = TRY(vm.this_value().to_object(vm));
+
+    // 3. Return ? HasOwnProperty(O, P).
     return Value(TRY(this_object->has_own_property(property_key)));
 }
 
+// 20.1.3.3 Object.prototype.isPrototypeOf ( V ), https://tc39.es/ecma262/#sec-object.prototype.isprototypeof
+JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::is_prototype_of)
+{
+    auto object_argument = vm.argument(0);
+
+    // 1. If V is not an Object, return false.
+    if (!object_argument.is_object())
+        return Value(false);
+    auto* object = &object_argument.as_object();
+
+    // 2. Let O be ? ToObject(this value).
+    auto this_object = TRY(vm.this_value().to_object(vm));
+
+    // 3. Repeat,
+    for (;;) {
+        // a. Set V to ? V.[[GetPrototypeOf]]().
+        object = TRY(object->internal_get_prototype_of());
+
+        // b. If V is null, return false.
+        if (!object)
+            return Value(false);
+
+        // c. If SameValue(O, V) is true, return true.
+        if (same_value(this_object, object))
+            return Value(true);
+    }
+}
+
+// 20.1.3.4 Object.prototype.propertyIsEnumerable ( V ), https://tc39.es/ecma262/#sec-object.prototype.propertyisenumerable
+JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::property_is_enumerable)
+{
+    // 1. Let P be ? ToPropertyKey(V).
+    auto property_key = TRY(vm.argument(0).to_property_key(vm));
+
+    // 2. Let O be ? ToObject(this value).
+    auto this_object = TRY(vm.this_value().to_object(vm));
+
+    // 3. Let desc be ? O.[[GetOwnProperty]](P).
+    auto property_descriptor = TRY(this_object->internal_get_own_property(property_key));
+
+    // 4. If desc is undefined, return false.
+    if (!property_descriptor.has_value())
+        return Value(false);
+
+    // 5. Return desc.[[Enumerable]].
+    return Value(*property_descriptor->enumerable);
+}
+
+// 20.1.3.5 Object.prototype.toLocaleString ( [ reserved1 [ , reserved2 ] ] ), https://tc39.es/ecma262/#sec-object.prototype.tolocalestring
+JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::to_locale_string)
+{
+    // 1. Let O be the this value.
+    auto this_value = vm.this_value();
+
+    // 2. Return ? Invoke(O, "toString").
+    return this_value.invoke(vm, vm.names.toString);
+}
+
 // 20.1.3.6 Object.prototype.toString ( ), https://tc39.es/ecma262/#sec-object.prototype.tostring
 JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::to_string)
 {
@@ -133,153 +196,169 @@ JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::to_string)
     return PrimitiveString::create(vm, DeprecatedString::formatted("[object {}]", tag));
 }
 
-// 20.1.3.5 Object.prototype.toLocaleString ( [ reserved1 [ , reserved2 ] ] ), https://tc39.es/ecma262/#sec-object.prototype.tolocalestring
-JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::to_locale_string)
-{
-    auto this_value = vm.this_value();
-    return this_value.invoke(vm, vm.names.toString);
-}
-
 // 20.1.3.7 Object.prototype.valueOf ( ), https://tc39.es/ecma262/#sec-object.prototype.valueof
 JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::value_of)
 {
+    // 1. Return ? ToObject(this value).
     return TRY(vm.this_value().to_object(vm));
 }
 
-// 20.1.3.4 Object.prototype.propertyIsEnumerable ( V ), https://tc39.es/ecma262/#sec-object.prototype.propertyisenumerable
-JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::property_is_enumerable)
+// 20.1.3.8.1 get Object.prototype.__proto__, https://tc39.es/ecma262/#sec-get-object.prototype.__proto__
+JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::proto_getter)
 {
-    // 1. Let P be ? ToPropertyKey(V).
-    auto property_key = TRY(vm.argument(0).to_property_key(vm));
-    // 2. Let O be ? ToObject(this value).
-    auto this_object = TRY(vm.this_value().to_object(vm));
-    // 3. Let desc be ? O.[[GetOwnProperty]](P).
-    auto property_descriptor = TRY(this_object->internal_get_own_property(property_key));
-    // 4. If desc is undefined, return false.
-    if (!property_descriptor.has_value())
-        return Value(false);
-    // 5. Return desc.[[Enumerable]].
-    return Value(*property_descriptor->enumerable);
+    // 1. Let O be ? ToObject(this value).
+    auto object = TRY(vm.this_value().to_object(vm));
+
+    // 2. Return ? O.[[GetPrototypeOf]]().
+    return TRY(object->internal_get_prototype_of());
 }
 
-// 20.1.3.3 Object.prototype.isPrototypeOf ( V ), https://tc39.es/ecma262/#sec-object.prototype.isprototypeof
-JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::is_prototype_of)
+// 20.1.3.8.2 set Object.prototype.__proto__, https://tc39.es/ecma262/#sec-set-object.prototype.__proto__
+JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::proto_setter)
 {
-    auto object_argument = vm.argument(0);
-    if (!object_argument.is_object())
-        return Value(false);
-    auto* object = &object_argument.as_object();
-    auto this_object = TRY(vm.this_value().to_object(vm));
+    auto proto = vm.argument(0);
 
-    for (;;) {
-        object = TRY(object->internal_get_prototype_of());
-        if (!object)
-            return Value(false);
-        if (same_value(this_object, object))
-            return Value(true);
+    // 1. Let O be ? RequireObjectCoercible(this value).
+    auto object = TRY(require_object_coercible(vm, vm.this_value()));
+
+    // 2. If proto is not an Object and proto is not null, return undefined.
+    if (!proto.is_object() && !proto.is_null())
+        return js_undefined();
+
+    // 3. If O is not an Object, return undefined.
+    if (!object.is_object())
+        return js_undefined();
+
+    // 4. Let status be ? O.[[SetPrototypeOf]](proto).
+    auto status = TRY(object.as_object().internal_set_prototype_of(proto.is_object() ? &proto.as_object() : nullptr));
+
+    // 5. If status is false, throw a TypeError exception.
+    if (!status) {
+        // FIXME: Improve/contextualize error message
+        return vm.throw_completion<TypeError>(ErrorType::ObjectSetPrototypeOfReturnedFalse);
     }
+
+    // 6. Return undefined.
+    return js_undefined();
 }
 
-// B.2.2.2 Object.prototype.__defineGetter__ ( P, getter ), https://tc39.es/ecma262/#sec-object.prototype.__defineGetter__
+// 20.1.3.9.1 Object.prototype.__defineGetter__ ( P, getter ), https://tc39.es/ecma262/#sec-object.prototype.__defineGetter__
 JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::define_getter)
 {
+    auto property = vm.argument(0);
+    auto getter = vm.argument(1);
+
+    // 1. Let O be ? ToObject(this value).
     auto object = TRY(vm.this_value().to_object(vm));
 
-    auto getter = vm.argument(1);
+    // 2. If IsCallable(getter) is false, throw a TypeError exception.
     if (!getter.is_function())
         return vm.throw_completion<TypeError>(ErrorType::NotAFunction, TRY_OR_THROW_OOM(vm, getter.to_string_without_side_effects()));
 
+    // 3. Let desc be PropertyDescriptor { [[Get]]: getter, [[Enumerable]]: true, [[Configurable]]: true }.
     auto descriptor = PropertyDescriptor { .get = &getter.as_function(), .enumerable = true, .configurable = true };
 
-    auto key = TRY(vm.argument(0).to_property_key(vm));
+    // 4. Let key be ? ToPropertyKey(P).
+    auto key = TRY(property.to_property_key(vm));
 
+    // 5. Perform ? DefinePropertyOrThrow(O, key, desc).
     TRY(object->define_property_or_throw(key, descriptor));
 
+    // 6. Return undefined.
     return js_undefined();
 }
 
-// B.2.2.3 Object.prototype.__defineSetter__ ( P, getter ), https://tc39.es/ecma262/#sec-object.prototype.__defineSetter__
+// 20.1.3.9.2 Object.prototype.__defineSetter__ ( P, setter ), https://tc39.es/ecma262/#sec-object.prototype.__defineSetter__
 JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::define_setter)
 {
+    auto property = vm.argument(0);
+    auto setter = vm.argument(1);
+
+    // 1. Let O be ? ToObject(this value).
     auto object = TRY(vm.this_value().to_object(vm));
 
-    auto setter = vm.argument(1);
+    // 2. If IsCallable(setter) is false, throw a TypeError exception.
     if (!setter.is_function())
         return vm.throw_completion<TypeError>(ErrorType::NotAFunction, TRY_OR_THROW_OOM(vm, setter.to_string_without_side_effects()));
 
+    // 3. Let desc be PropertyDescriptor { [[Set]]: setter, [[Enumerable]]: true, [[Configurable]]: true }.
     auto descriptor = PropertyDescriptor { .set = &setter.as_function(), .enumerable = true, .configurable = true };
 
-    auto key = TRY(vm.argument(0).to_property_key(vm));
+    // 4. Let key be ? ToPropertyKey(P).
+    auto key = TRY(property.to_property_key(vm));
 
+    // 5. Perform ? DefinePropertyOrThrow(O, key, desc).
     TRY(object->define_property_or_throw(key, descriptor));
 
+    // 6. Return undefined.
     return js_undefined();
 }
 
-// B.2.2.4 Object.prototype.__lookupGetter__ ( P ), https://tc39.es/ecma262/#sec-object.prototype.__lookupGetter__
+// 20.1.3.9.3 Object.prototype.__lookupGetter__ ( P ), https://tc39.es/ecma262/#sec-object.prototype.__lookupGetter__
 JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::lookup_getter)
 {
+    auto property = vm.argument(0);
+
+    // 1. Let O be ? ToObject(this value).
     auto object = GCPtr { TRY(vm.this_value().to_object(vm)) };
 
-    auto key = TRY(vm.argument(0).to_property_key(vm));
+    // 2. Let key be ? ToPropertyKey(P).
+    auto key = TRY(property.to_property_key(vm));
 
+    // 3. Repeat,
     while (object) {
+        // a. Let desc be ? O.[[GetOwnProperty]](key).
         auto desc = TRY(object->internal_get_own_property(key));
+
+        // b. If desc is not undefined, then
         if (desc.has_value()) {
+            // i. If IsAccessorDescriptor(desc) is true, return desc.[[Get]].
             if (desc->is_accessor_descriptor())
                 return *desc->get ?: js_undefined();
+
+            // ii. Return undefined.
             return js_undefined();
         }
+
+        // c. Set O to ? O.[[GetPrototypeOf]]().
         object = TRY(object->internal_get_prototype_of());
     }
 
+    // d. If O is null, return undefined.
     return js_undefined();
 }
 
-// B.2.2.5 Object.prototype.__lookupSetter__ ( P ), https://tc39.es/ecma262/#sec-object.prototype.__lookupSetter__
+// 20.1.3.9.4 Object.prototype.__lookupSetter__ ( P ), https://tc39.es/ecma262/#sec-object.prototype.__lookupSetter__
 JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::lookup_setter)
 {
+    auto property = vm.argument(0);
+
+    // 1. Let O be ? ToObject(this value).
     auto object = GCPtr { TRY(vm.this_value().to_object(vm)) };
 
-    auto key = TRY(vm.argument(0).to_property_key(vm));
+    // 2. Let key be ? ToPropertyKey(P).
+    auto key = TRY(property.to_property_key(vm));
 
+    // 3. Repeat,
     while (object) {
+        // a. Let desc be ? O.[[GetOwnProperty]](key).
         auto desc = TRY(object->internal_get_own_property(key));
+
+        // b. If desc is not undefined, then
         if (desc.has_value()) {
+            // i. If IsAccessorDescriptor(desc) is true, return desc.[[Set]].
             if (desc->is_accessor_descriptor())
                 return *desc->set ?: js_undefined();
+
+            // ii. Return undefined.
             return js_undefined();
         }
+
+        // c. Set O to ? O.[[GetPrototypeOf]]().
         object = TRY(object->internal_get_prototype_of());
     }
 
-    return js_undefined();
-}
-
-// B.2.2.1.1 get Object.prototype.__proto__, https://tc39.es/ecma262/#sec-get-object.prototype.__proto__
-JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::proto_getter)
-{
-    auto object = TRY(vm.this_value().to_object(vm));
-    return TRY(object->internal_get_prototype_of());
-}
-
-// B.2.2.1.2 set Object.prototype.__proto__, https://tc39.es/ecma262/#sec-set-object.prototype.__proto__
-JS_DEFINE_NATIVE_FUNCTION(ObjectPrototype::proto_setter)
-{
-    auto object = TRY(require_object_coercible(vm, vm.this_value()));
-
-    auto proto = vm.argument(0);
-    if (!proto.is_object() && !proto.is_null())
-        return js_undefined();
-
-    if (!object.is_object())
-        return js_undefined();
-
-    auto status = TRY(object.as_object().internal_set_prototype_of(proto.is_object() ? &proto.as_object() : nullptr));
-    if (!status) {
-        // FIXME: Improve/contextualize error message
-        return vm.throw_completion<TypeError>(ErrorType::ObjectSetPrototypeOfReturnedFalse);
-    }
+    // d. If O is null, return undefined.
     return js_undefined();
 }