Function reduce

purl.js:174–183

(obj, accumulator)

    }

    function reduce(obj, accumulator){
        var i = 0,
            l = obj.length >> 0,
            curr = arguments[2];
        while (i < l) {
            if (i in obj) curr = accumulator.call(undefined, curr, obj[i], i, obj);
            ++i;
        }
        return curr;
    }

    function isArray(vArg) {
        return Object.prototype.toString.call(vArg) === "[object Array]";