Function binder

implementation.js:50–66

()

    var bound;
    var binder = function () {
        if (this instanceof bound) {
            var result = target.apply(
                this,
                concatty(args, arguments)
            );
            if (Object(result) === result) {
                return result;
            }
            return this;
        }
        return target.apply(
            that,
            concatty(args, arguments)
        );

    };

    var boundLength = max(0, target.length - args.length);
    var boundArgs = [];