var _ = require("./_");

module.exports = function (fn, self) {
    return function () {
        var args, cb, j;
        args = 2 <= arguments.length ?
            _.slice.call(arguments, 0, j = arguments.length - 1) :
            (j = 0, []), cb = arguments[j++];

        var isFn = _.isFunction(cb);

        if (!isFn) {
            args.push(cb);
            return fn.apply(self, args);
        }

        return fn.apply(self, args).then(function (val) {
            cb(null, val);
        })["catch"](cb);
    };
};