sebastienros.jint/Jint/Native/WeakSet/WeakSetConstructor.cs

using Jint.Native.Function;
using Jint.Native.Object;
using Jint.Runtime;
using Jint.Runtime.Descriptors;

namespace Jint.Native.WeakSet
{
    internal sealed class WeakSetConstructor : Constructor
    {
        private static readonly JsString _functionName = new("WeakSet");

        internal WeakSetConstructor(
            Engine engine,
            Realm realm,
            FunctionPrototype functionPrototype,
            ObjectPrototype objectPrototype)
            : base(engine, realm, _functionName)
        {
            _prototype = functionPrototype;
            PrototypeObject = new WeakSetPrototype(engine, realm, this, objectPrototype);
            _length = new PropertyDescriptor(0, PropertyFlag.Configurable);
            _prototypeDescriptor = new PropertyDescriptor(PrototypeObject, PropertyFlag.AllForbidden);
        }

        private WeakSetPrototype PrototypeObject { get; }

        public override ObjectInstance Construct(JsValue[] arguments, JsValue newTarget)
        {
            if (newTarget.IsUndefined())
            {
                ExceptionHelper.ThrowTypeError(_realm);
            }

            var set = OrdinaryCreateFromConstructor(
                newTarget,
                static intrinsics => intrinsics.WeakSet.PrototypeObject,
                static (Engine engine, Realm _, object? _) => new JsWeakSet(engine));

            var arg1 = arguments.At(0);
            if (!arg1.IsNullOrUndefined())
            {
                var adder = set.Get("add") as ICallable;

                // check fast path
                if (arg1 is JsArray array && ReferenceEquals(adder, _engine.Realm.Intrinsics.WeakSet.PrototypeObject._originalAddFunction))
                {
                    foreach (var value in array)
                    {
                        set.WeakSetAdd(value);
                    }

                    return set;
                }

                if (adder is null)
                {
                    ExceptionHelper.ThrowTypeError(_realm, "add must be callable");
                }

                var iterable = arguments.At(0).GetIterator(_realm);

                try
                {
                    var args = new JsValue[1];
                    do
                    {
                        if (!iterable.TryIteratorStep(out var next))
                        {
                            return set;
                        }

                        var nextValue = next.Get(CommonProperties.Value);
                        args[0] = nextValue;
                        adder.Call(set, args);
                    } while (true);
                }
                catch
                {
                    iterable.Close(CompletionType.Throw);
                    throw;
                }
            }

            return set;
        }
    }
}