自己照着Promise/A规范写的Promise库

摘要：试图写了一下大概测试了一下没有用专业的测试工具测试代码感觉还是写的比较好懂的，本人水平较差，如果测试有问题，欢迎回复指出地址同一执行队列中原生是先于实现的自己实现暂时用模拟必须传入并且构造状态改变之后传递的值执行之后返回的这里必须异步处理否

试图写了一下,大概测试了一下,没有用专业的测试工具测试....

代码感觉还是写的比较好懂的，本人水平较差，如果测试有问题，欢迎回复指出
地址： https://github.com/julyL/Code...

(function(global) {
    function isFunction(val) {
        return typeof val == "function";
    }

    function isObject(val) {
        return typeof val == "object";
    }

    function asyncExcute(fn) {
        return function() {
            setTimeout(fn); // 同一执行队列中,原生Promise是先于setTimeout实现的,自己实现暂时用setTimeout模拟
        }
    }
    function Promise(fn) {
        if (!isFunction(fn) || this instanceof Promise == false) {
            throw new TypeError("Promise必须传入function并且new构造")
        }
        this.status = "pending";
        this.value = undefined; //  promise状态改变之后传递的值
        this.thenPromise = undefined; //执行then之后返回的promise
        this.resolveQueue = []; //
        this.rejectQueue = []; //   
        var re = asyncExcute(function(resolveData) { this._resolve(resolveData) }.bind(this)), //这里必须异步处理,否则then函数执行以前可能就已经执行了_resolve,但这时then中函数还未加入resolveQueue中
            rj = asyncExcute(function(resolveData) { this._reject(resolveData) }.bind(this));
        try {
            fn(re, rj)
        } catch (error) {
            this.status = "reject";
            this.value = error;
            asyncExcute(function(){this._reject(error)});         //  new Promise(()=>{ 出现异常... }).then(refn,rjfn);    出现异常时then还未执行, rjfn还未加入到rejectQueue中  
        }
    }
    Promise.prototype.then = function(refn, rjfn) {
        var returnPro = new Promise(function() {});
        this.thenPromise = returnPro;
        this.resolveQueue.push(refn);
        this.rejectQueue.push(rjfn);

        if (this.status == "resolve") { //执行then时,如果状态已经不是pending,则执行相应函数
            this._resolve(this.value);
        }
        if (this.status == "reject") {
            this._reject(this.value);
        }
        return returnPro;
    }
    Promise.prototype._resolve = function(resolveData) {
        var handle,
            returnVal;
        this.status = "resolve";
        this.value = resolveData;
        while (this.resolveQueue.length > 0) { //2.2.6  当 promise 成功执行时，所有 onFulfilled 需按照其注册顺序依次回调
            handle = this.resolveQueue.shift();
            if (!isFunction(handle)) { //不是函数  2.1.1 onFulfilled 不是函数，其必须被忽略
                this.thenPromise.value = resolveData;
                this.thenPromise.status = "resolve";
                this.thenPromise._resolve();
                return;
            }
            try { //如果 onFulfilled 或者 onRejected 抛出一个异常 e ，则 promise2 必须拒绝执行，并返回拒因 e
                returnVal = handle(resolveData);
            } catch (error) {
                this.thenPromise.status = "reject";
                this.thenPromise.value = error;
                this.thenPromise._reject();
            }
            if (isObject(returnVal || isFunction(returnVal))) { //如果返回值为对象或者函数
                if (returnVal == this.thenPromise) { //如果 promise 和 x 指向同一对象，以 TypeError 为据因拒绝执行 promise
                    this.thenPromise.status = "reject";
                    this.thenPromise.value = new TypeError("[[Resolve]](promise, x),promise 和 x 不能指向同一对象");
                } else if (returnVal instanceof Promise) { //如果 x 为 Promise ，则使 promise 接受 x 的状态
                    try {
                        then.call(returnVal, this.thenPromise._resolve.bind(this.thenPromise), this.thenPromise._reject.bind(this.thenPromise));
                    } catch (error) {
                        this.thenPromise.status = "reject";
                        this.thenPromise.value = error;
                        this.thenPromise._reject();
                    }
                } else { //如果 x 为对象或者函数
                    try { //如果取 x.then 的值时抛出错误 e ，则以 e 为据因拒绝 promise
                        var then = returnVal.then;
                        if (isFunction(then)) {
                            then.call(returnVal, this.thenPromise._resolve.bind(this.thenPromise), this.thenPromise._reject.bind(this.thenPromise));
                        }
                    } catch (error) {
                        this.thenPromise.status = "reject";
                        this.thenPromise.value = error;
                        this.thenPromise._reject();
                    }
                }
            } else {
                this.thenPromise.value = returnVal;
                this.thenPromise.status = "resolve";
                this.thenPromise._resolve();
            }
        }
    }

    Promise.prototype._reject = function(resolveData) {
        var handle,
            returnVal;
        this.status = "resolve";
        this.value = resolveData;
        while (this.rejectQueue.length > 0) {     //2.2.6  当 promise 成功执行时，所有 onFulfilled 需按照其注册顺序依次回调
            handle = this.rejectQueue.shift();
            if (!isFunction(handle)) {          //不是函数  2.1.1 onFulfilled 不是函数，其必须被忽略
                this.thenPromise.value = resolveData;
                this.thenPromise.status = "resolve";
                this.thenPromise._resolve();
                return;
            }
            try { //如果 onFulfilled 或者 onRejected 抛出一个异常 e ，则 promise2 必须拒绝执行，并返回拒因 e
                returnVal = handle(resolveData);
            } catch (error) {
                this.thenPromise.status = "reject";
                this.thenPromise.value = error;
                this.thenPromise._reject();
            }
            if (isObject(returnVal || isFunction(returnVal))) { //如果返回值为对象或者函数
                if (returnVal == this.thenPromise) { //如果 promise 和 x 指向同一对象，以 TypeError 为据因拒绝执行 promise
                    this.thenPromise.status = "reject";
                    this.thenPromise.value = new TypeError("[[Resolve]](promise, x),promise 和 x 不能指向同一对象");
                } else if (returnVal instanceof Promise) { //如果 x 为 Promise ，则使 promise 接受 x 的状态
                    try {
                        then.call(returnVal, this.thenPromise._resolve.bind(this.thenPromise), this.thenPromise._reject.bind(this.thenPromise));
                    } catch (error) {
                        this.thenPromise.status = "reject";
                        this.thenPromise.value = error;
                        this.thenPromise._reject();
                    }
                } else {      //如果 x 为对象或者函数
                    try {     //如果取 x.then 的值时抛出错误 e ，则以 e 为据因拒绝 promise
                        var then = returnVal.then;
                        if (isFunction(then)) {
                            then.call(returnVal, this.thenPromise._resolve.bind(this.thenPromise), this.thenPromise._reject.bind(this.thenPromise));
                        }
                    } catch (error) {
                        this.thenPromise.status = "reject";
                        this.thenPromise.value = error;
                        this.thenPromise._reject();
                    }
                }
            } else {
                this.thenPromise.value = returnVal;
                this.thenPromise.status = "resolve";
                this.thenPromise._resolve();
            }
        }
    }

    Promise.resolve = function(value) {
        return new Promise(function(re, rj) {
            re(value)
        })
    }
    Promise.reject = function(value) {
        return new Promise(function(re, rj) {
            re(value)
        })
    }
    Promise.all = function(queue) {
        if (Object.prototype.toString.call(queue) != "[object Array]") {
            return;
        }
        var returnPromise = new Promise(function() {}),
            resolveNum = 0;
        for (var i = 0; i < queue.length; i++) {
            queue[i].then(function() {
                resolveNum++;
                if (resolveNum == queue.length) {
                    returnPromise._resolve();
                }
            });
        }
        return returnPromise;
    }
    Promise.race = function(queue) {
        if (Object.prototype.toString.call(queue) != "[object Array]") {
            return;
        }
        var returnPromise = new Promise(function() {}),
            resolveNum = 0;
        for (var i = 0; i < queue.length; i++) {
            queue[i].then(function() {
                returnPromise._resolve();
            });
        }
        return returnPromise;
    }
    global.Promise = Promise;
})(window);