Queue - serial queue processing

var queue = require('queue');
var input = [1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13];
var q = queue();
q.concurrency = 1;

function test(element) {
    return (function (cb) {
        setTimeout(function() {
            console.log(element);
            cb();
        }, Math.random()*2000);
    });
}

input.forEach(function (element) {
    var _test = test(element);
    q.push(_test);
}, this);

q.on('end', function () {
    console.log("all done");
})
q.on('success', function (result, job) {
    console.log('job finished processing:');
});

q.start();