Array batch execution

array-batch.js

function batch(array, size, callback, done) {
    var index = 0,
        processed = 0;

    while (index < size) {
        next();
    }

    function next() {
        var item = array[index];

        if (item) {
            callback(item, index, function () {
                processed++;

                if (array[index]) { 
                    next();
                }
                else if (processed === array.length && done) {
                    done();
                }
            });
        }

        index++;
    }
}

Kill the server with simultaneous calls

Usage

var batchSize = 3;
var array = ["a", "b", "c", "d", "e"];

batch(array, batchSize, function(item, index, next) {
    someAsyncFunc(item, function callback() {
        doSomeStuff();

        // we are done, now lets go to the next step
        next();
    });
}, function () {
    // all calls have been succeeded, do something about
    finishProcess();
});