Jurassic.Library.PropertyDescriptor.FromObject C# (CSharp) Method

        public static PropertyDescriptor FromObject(ObjectInstance obj, PropertyDescriptor defaults)
        {
            if (obj == null)
                return PropertyDescriptor.Undefined;

            // Read configurable attribute.
            bool configurable = defaults.IsConfigurable;
            if (obj.HasProperty("configurable"))
                configurable = TypeConverter.ToBoolean(obj["configurable"]);

            // Read writable attribute.
            bool writable = defaults.IsWritable;
            if (obj.HasProperty("writable"))
                writable = TypeConverter.ToBoolean(obj["writable"]);

            // Read enumerable attribute.
            bool enumerable = defaults.IsEnumerable;
            if (obj.HasProperty("enumerable"))
                enumerable = TypeConverter.ToBoolean(obj["enumerable"]);

            // Read property value.
            object value = defaults.Value;
            if (obj.HasProperty("value"))
                value = obj["value"];

            // The descriptor is an accessor if get or set is present.
            bool isAccessor = false;

            // Read get accessor.
            FunctionInstance getter = defaults.Getter;
            if (obj.HasProperty("get"))
            {
                if (obj.HasProperty("value"))
                    throw new JavaScriptException(obj.Engine, ErrorType.TypeError, "Property descriptors cannot have both 'get' and 'value' set");
                if (obj.HasProperty("writable"))
                    throw new JavaScriptException(obj.Engine, ErrorType.TypeError, "Property descriptors with 'get' or 'set' defined must not have 'writable' set");
                if (obj["get"] is FunctionInstance)
                    getter = (FunctionInstance)obj["get"];
                else if (TypeUtilities.IsUndefined(obj["get"]) == true)
                    getter = null;
                else
                    throw new JavaScriptException(obj.Engine, ErrorType.TypeError, "Property descriptor 'get' must be a function");
                isAccessor = true;
            }

            // Read set accessor.
            FunctionInstance setter = defaults.Setter;
            if (obj.HasProperty("set"))
            {
                if (obj.HasProperty("value"))
                    throw new JavaScriptException(obj.Engine, ErrorType.TypeError, "Property descriptors cannot have both 'set' and 'value' set");
                if (obj.HasProperty("writable"))
                    throw new JavaScriptException(obj.Engine, ErrorType.TypeError, "Property descriptors with 'get' or 'set' defined must not have 'writable' set");
                if (obj["set"] is FunctionInstance)
                    setter = (FunctionInstance)obj["set"];
                else if (TypeUtilities.IsUndefined(obj["set"]) == true)
                    setter = null;
                else
                    throw new JavaScriptException(obj.Engine, ErrorType.TypeError, "Property descriptor 'set' must be a function");
                isAccessor = true;
            }

            // Build up the attributes enum.
            PropertyAttributes attributes = PropertyAttributes.Sealed;
            if (configurable == true)
                attributes |= PropertyAttributes.Configurable;
            if (writable == true)
                attributes |= PropertyAttributes.Writable;
            if (enumerable == true)
                attributes |= PropertyAttributes.Enumerable;

            // Either a value or an accessor is possible.
            object descriptorValue = value;
            if (isAccessor == true)
                descriptorValue = new PropertyAccessorValue(getter, setter);

            // Create the new property descriptor.
            return new PropertyDescriptor(descriptorValue, attributes);
        }

        public static ObjectInstance DefineProperty([JSParameter(JSParameterFlags.DoNotConvert)] ObjectInstance obj, string propertyName, [JSParameter(JSParameterFlags.DoNotConvert)] ObjectInstance attributes)
        {
            var defaults   = obj.GetOwnPropertyDescriptor(propertyName);
            var descriptor = PropertyDescriptor.FromObject(attributes, defaults);

            obj.DefineProperty(propertyName, descriptor, true);
            return(obj);
        }