sebastienros.jint/Jint/Native/Json/JsonInstance.cs

using Jint.Native.Object;
using Jint.Native.Symbol;
using Jint.Runtime;
using Jint.Runtime.Descriptors;
using Jint.Runtime.Interop;

namespace Jint.Native.Json;

internal sealed class JsonInstance : ObjectInstance
{
    private readonly Realm _realm;

    internal JsonInstance(
        Engine engine,
        Realm realm,
        ObjectPrototype objectPrototype)
        : base(engine)
    {
        _realm = realm;
        _prototype = objectPrototype;
    }

    protected override void Initialize()
    {
        var properties = new PropertyDictionary(2, checkExistingKeys: false)
        {
#pragma warning disable 618
            ["parse"] = new PropertyDescriptor(new ClrFunction(Engine, "parse", Parse, 2, PropertyFlag.Configurable), true, false, true),
            ["stringify"] = new PropertyDescriptor(new ClrFunction(Engine, "stringify", Stringify, 3, PropertyFlag.Configurable), true, false, true)
#pragma warning restore 618
        };
        SetProperties(properties);

        var symbols = new SymbolDictionary(1)
        {
            [GlobalSymbolRegistry.ToStringTag] = new PropertyDescriptor("JSON", false, false, true),
        };
        SetSymbols(symbols);
    }

    private static JsValue InternalizeJSONProperty(JsValue holder, JsValue name, ICallable reviver)
    {
        var temp = holder.Get(name);
        if (temp is ObjectInstance val)
        {
            if (val.IsArray())
            {
                var i = 0UL;
                var len = TypeConverter.ToLength(val.Get(CommonProperties.Length));
                while (i < len)
                {
                    var prop = JsString.Create(i);
                    var newElement = InternalizeJSONProperty(val, prop, reviver);
                    if (newElement.IsUndefined())
                    {
                        val.Delete(prop);
                    }
                    else
                    {
                        val.CreateDataProperty(prop, newElement);
                    }
                    i = i + 1;
                }
            }
            else
            {
                var keys = val.EnumerableOwnProperties(EnumerableOwnPropertyNamesKind.Key);
                foreach (var p in keys)
                {
                    var newElement = InternalizeJSONProperty(val, p, reviver);
                    if (newElement.IsUndefined())
                    {
                        val.Delete(p);
                    }
                    else
                    {
                        val.CreateDataProperty(p, newElement);
                    }
                }
            }
        }

        return reviver.Call(holder, name, temp);
    }

    /// <summary>
    /// https://tc39.es/ecma262/#sec-json.parse
    /// </summary>
    private JsValue Parse(JsValue thisObject, JsCallArguments arguments)
    {
        var jsonString = TypeConverter.ToString(arguments.At(0));
        var reviver = arguments.At(1);

        var parser = new JsonParser(_engine);
        var unfiltered = parser.Parse(jsonString);

        if (reviver.IsCallable)
        {
            var root = _realm.Intrinsics.Object.Construct(Arguments.Empty);
            var rootName = JsString.Empty;
            root.CreateDataPropertyOrThrow(rootName, unfiltered);
            return InternalizeJSONProperty(root, rootName, (ICallable) reviver);
        }
        else
        {
            return unfiltered;
        }
    }

    private JsValue Stringify(JsValue thisObject, JsCallArguments arguments)
    {
        var value = arguments.At(0);
        var replacer = arguments.At(1);
        var space = arguments.At(2);

        if (value.IsUndefined() && replacer.IsUndefined())
        {
            return Undefined;
        }

        var serializer = new JsonSerializer(_engine);
        return serializer.Serialize(value, replacer, space);
    }
}