example of node.js Async series function

async_series.js

async.series({
        one: function (callback) {
            setTimeout(function () {
                callback(null, 1);
            }, 200);
        },
        two: function (callback) {
            setTimeout(function () {
                callback(null, 2);
            }, 100);
        }
    },
    function (err, results) {
        // results is now equal to: {one: 1, two: 2}
    });