Queue JS

queue.js

function Queue() {
    var self = this;
    self.queue = [];

    self.push = function (fn, context, params) {
        params = params || [];
        context = context || this;
        self.queue.push({fn: fn, params: params, context: context});
        return self;
    };
    self.pushFront = function (fn, context, params) {
        params = params || [];
        context = context || this;
        self.queue.unshift({fn: fn, params: params, context: context});
        return self;
    };
    function callback() {
        if (self.queue.length > 0) {
            var item = self.queue.pop();
            var args = item.params;
            args.push(callback);
            item.fn.apply(item.context, args);
        }else{
            self.final();
        }
    }

    self.start = function (cb) {
        self.final = cb;
        callback();
    }
}
var q = new Queue();
q.push(function (cb) {
    console.log(1);
    setTimeout(function () {
        cb();
    }, 2000);
}, this);
q.push(function (cb) {
    console.log(2);
    setTimeout(function () {
        cb();
    }, 1000);
}, this);
q.push(function (cb) {
    console.log(3);
    setTimeout(function () {
        cb();
    }, 3000);
}, this);

q.start(function () {
    console.log('done');
});