public override void VisitIsExpression (IsExpression isExpression) { base.VisitIsExpression (isExpression); var p = isExpression.Type as PrimitiveType; if (p != null) { var e = isExpression.Expression; e.Remove (); var n = new BinaryOperatorExpression ( new MemberReferenceExpression (e, "constructor"), BinaryOperatorType.Equality, new TypeReferenceExpression (GetJsConstructorType (isExpression.Type))); isExpression.ReplaceWith (n); } }