Waiter.js

var Waiter = function() {
    var dfd = [],
        doneArr = [],
        failArr = [],
        slice = Array.prototype.slice,
        that = this;
    var Primise = function() {
        this.resolved = false;
        this.rejected = false;
    }
    Primise.prototype = {
        resolve: function() {

            this.resolved = true;
            if (!dfd.length) {
                return;
            }
            for (var i = dfd.length - 1; i >= 0; i--) {
                if (dfd[i] && !dfd[i].resolved || dfd[i].rejected) {
                    return;
                }
                dfd.splice(i, 1);
            }
            _exec(doneArr);
        },
        reject: function() {
            this.rejected = true;
            if (!dfd.length) {
                return;
            }
            dfd.splice(0);
            _exec(failArr);
        }
    }
    that.Deferred = function() {
        return new Primise();
    }

    function _exec(arr) {
        var i = 0,
            len = arr.length;
        for (; i < len; i++) {
            try {
                arr[i] && arr[i]();
            } catch (e) {}
        }
    };
    that.when = function() {

        dfd = slice.call(arguments);
        var i = dfd.length;
        for (--i; i >= 0; i--) {
            if (!dfd[i] || dfd[i].resolved || dfd[i].rejected || !dfd[i] instanceof Primise) {
                dfd.splice(i, 1);
            }
        }
        return that;
    };
    that.done = function() {

        doneArr = doneArr.concat(slice.call(arguments));
        return that;
    };
    that.fail = function() {
        failArr = failArr.concat(slice.call(arguments));
        return that;
    };
};

var waiter = new Waiter();


var first = function() {
    var dtd = waiter.Deferred();
    setTimeout(function() {
        console.log('first finish');
        dtd.resolve();
    }, 5000);
    return dtd;
}();

var second = function() {
    var dtd = waiter.Deferred();
    setTimeout(function() {
        console.log('second finish');
        dtd.resolve();
    }, 0);
    return dtd;
}();

waiter.when(first, second).done(function() {
    console.log('first success');
}, function() {
    console.log('second success');
}).fail(function() {
    console.log('fail');
})