Jazzychad's Array iteration question.

gistfile1.txt

var add1 = function (arr, val, n) {
    //Callback function for the reduce method.
    var cb = function(remaining, cur, i, arr) {
        if(cur === val && remaining > 0) {
            arr[i]++;
            --remaining;
        }
        return remaining;
    }

    if(n === Math.abs(n)) {
        arr.reduce(cb, n || arr.length);
    } else {
        arr.reduceRight(cb, (-n));
    }
}