"exclude" option could be used multiple times in this case the values are provided in an array
function (arg) {
                var value  = arg.value;
                var flag   = arg.flag;
                var result = null;

                if (value) {
                    value  = Array.isArray(value) ? value : [value];
                    result = [];

                    value.forEach(function (path) {
                        result.push(flag);
                        result.push(path);
                    });
                }

                return result;
            }