functional

functional

var _ = {};

var MAX_ARRAY_INDEX = Math.pow(2, 53) - 1;
function getLength(array) {
    return array == null ? void 0 : array.length;
}
function isArrayLike(array) {
    var length = getLength(array);
    return typeof length == 'number' && length >= 0 && length <= MAX_ARRAY_INDEX;
}

_.each = function (datas, iter) {
    if (isArrayLike(datas)) {
        for (var i = 0, len = datas.length; i < len; i++) {
            iter(datas[i], i, datas);
        }
    } else {
        for (var key in datas) {
            if (datas.hasOwnProperty(key)) {
                iter(datas[key], key, datas);
            }
        }
    }
}


var curryr = function (func) {
    return function (a) {
        if (arguments.length > 1) {
            return func.apply(null, arguments);
        }
        return function (b) {
            return func.call(null, b, a);
        }
    }
}

var _filter = curryr(function (data, iter) {
    var new_data = [];
    _.each(data, function (v) {
        if (iter(v)) {
            new_data.push(v);
        }
    })
    return new_data;
});

_.reduce = function (datas, iter, memo) {
    _.each(datas, function (data, i, datas) {
        memo = iter(memo, data, i, datas);
    });
    return memo;
}

_.groupBy = function (datas, iter) {
    return _.reduce(datas, function (grouped, data, i, datas) {
        var key = iter(data, i, datas);
        grouped.hasOwnProperty(key) ? grouped.push(data[key]) : grouped[key] = [data[key]];
        return grouped
    }, {})
}

_.compose = function () {
    var func = arguments;
    var start = func.length - 1;

    return function () {
        var result = func[start].apply(this, arguments);
        while (start--) result = func[start].call(this, result);
        return result;
    }
}

_.pipe = function () {
    var func = arguments;
    return function (seed) {
        return _.reduce(func, function (l, r) {
            return r(l);
        }, seed);
    }
}
_.rest = function (args, num) {
    return Array.prototype.slice.call(args, (num || 1));
}
_.go = function () {
    var funs = _.rest(arguments);
    return _.pipe.apply(null,funs)(arguments[0]);
}