/// <summary>
/// Determines whether an object has a non-inherited property
/// </summary>
/// <remarks>
/// Requires an active script context.
/// </remarks>
/// <param name="source">The JavaScript value</param>
/// <param name="propertyName">The name of the property</param>
/// <returns>Whether the object has the non-inherited property</returns>
public static bool HasOwnProperty(this JsValue source, string propertyName)
{
JsPropertyId propertyId = JsPropertyId.FromString(propertyName);
bool result = source.HasOwnProperty(propertyId);
return(result);
}
private JsValue Bind(JsValue thisObj, JsValue[] arguments)
{
if (!(thisObj is ICallable))
{
ExceptionHelper.ThrowTypeError(Engine, "Bind must be called on a function");
}
var thisArg = arguments.At(0);
var f = new BindFunctionInstance(Engine)
{
TargetFunction = thisObj,
BoundThis = thisObj is ArrowFunctionInstance ? Undefined : thisArg,
BoundArgs = arguments.Skip(1),
_prototype = Engine.Function.PrototypeObject,
};
JsNumber l;
var targetHasLength = thisObj.HasOwnProperty(CommonProperties.Length);
if (targetHasLength)
{
var targetLen = thisObj.Get(CommonProperties.Length);
if (!targetLen.IsNumber())
{
l = JsNumber.PositiveZero;
}
else
{
targetLen = TypeConverter.ToInteger(targetLen);
// first argument is target
var argumentsLength = System.Math.Max(0, arguments.Length - 1);
l = JsNumber.Create((uint)System.Math.Max(((JsNumber)targetLen)._value - argumentsLength, 0));
}
}
else
{
l = JsNumber.PositiveZero;
}
f._length = new PropertyDescriptor(l, PropertyFlag.Configurable);
var targetName = thisObj.Get(CommonProperties.Name);
if (!targetName.IsString())
{
targetName = JsString.Empty;
}
f.SetFunctionName(targetName, "bound");
return(f);
}
/// <summary>
/// https://tc39.es/ecma262/#sec-function.prototype.bind
/// </summary>
private JsValue Bind(JsValue thisObj, JsValue[] arguments)
{
if (thisObj is not ICallable)
{
ExceptionHelper.ThrowTypeError(_realm, "Bind must be called on a function");
}
var thisArg = arguments.At(0);
var f = BoundFunctionCreate((ObjectInstance)thisObj, thisArg, arguments.Skip(1));
JsNumber l;
var targetHasLength = thisObj.HasOwnProperty(CommonProperties.Length);
if (targetHasLength)
{
var targetLen = thisObj.Get(CommonProperties.Length);
if (targetLen is not JsNumber number)
{
l = JsNumber.PositiveZero;
}
else
{
if (number.IsPositiveInfinity())
{
l = number;
}
else if (number.IsNegativeInfinity())
{
l = JsNumber.PositiveZero;
}
else
{
var targetLenAsInt = (long)TypeConverter.ToIntegerOrInfinity(targetLen);
// first argument is target
var argumentsLength = System.Math.Max(0, arguments.Length - 1);
l = JsNumber.Create((ulong)System.Math.Max(targetLenAsInt - argumentsLength, 0));
}
}
}
