Javascript：自己写异步流程编程框架

背景

自从NodeJs出来以后，异步编程便更加系统化和框架话了，为了应对异步编程框架带来的深层嵌套问题，社区也出现了异步流程编程框架，本文主要对异步流程框架做一个简单的解析。

现配代码了

var Asy = function () {
};

Asy.start = function (action, success, failure) {
    var asy = new Asy();
    asy._addAction(action, success, failure);

    return asy;
}

Asy.emptyFun = function () { };

Asy.prototype.then = function (action, success, failure) {
    var me = this;

    me._addAction(action, success, failure);

    return me;
};

Asy.prototype._addAction = function (action, success, failure) {
    var me = this;

    me._actions = me._actions || [];

    me._actions.push({
        action: action || Asy.emptyFun,
        success: success || Asy.emptyFun,
        failure: failure || Asy.emptyFun
    });
};

Asy.prototype.execute = function () {
    var me = this;

    var length = me._actions.length;

    var resultFun = function () {
        var args = Array.prototype.slice.call(arguments)
                                  .concat([me._actions[length - 1].success, me._actions[length - 1].failure])

        me._actions[length - 1].action.apply(null, args);
    };

    for (var i = me._actions.length - 2; i >= 0 ; i--) {
        (function (action) {
            var oldResultFun = resultFun;

            resultFun = function () {
                var newSuccess = function () {
                    var args = Array.prototype.slice.call(arguments);
                    action.success.apply(null, args);
                    oldResultFun.apply(null, args);
                };

                var args = Array.prototype.slice.call(arguments)
                                          .concat([newSuccess, action.failure]);

                action.action.apply(null, args);
            };
        })(me._actions[i]);
    };

    var args = Array.prototype.slice.call(arguments);
    resultFun.apply(null, args);
}

var testAsyFun = function (i, success, failure) {
    setTimeout(function () {
        i = i + 1;

        success(i);
    }, 2000);
};

Asy
   .start(testAsyFun, function (i) {
       console.log("A:" + i);
   })
   .then(testAsyFun, function (i) {
       console.log("B:" + i)
   })
   .then(testAsyFun, function (i) {
       console.log("C:" + i)
   })
   //.wait([testAsyFun], [testAsyFun], function () {

   //})
   .execute(1);