###promise原理系列目录：

promise实现原理（一）promise.then

promise实现原理（二）promise.catch

promise实现原理（三）promise.finally

promise实现原理（四）promise.all与promise.race

promise实现原理（五）promise.allSettled与promise.any

promise实现原理（六）promise.resolve与promise.reject

promise实现最终版！合成代码

来看一下最终代码吧！

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function myPromise(callback) {
	var self = this;
	self.status = 'pending';//创建当前状态为pending
	self.data = null;//此变量为保存成功状态的数据使用
	self.callbackObj = {};//回调对象，用于存放.then中的回调
	
	self.doCallback=function(){//执行回调函数
		let callBackArr = []
		if(self.status == 'resolved'){//取构造函数中保存的data，传入callback方法里
			callBackArr = self.callbackObj.resolveCallback;
		}else if(self.status == 'rejected'){
			if(self.callbackObj.rejectCallBack[0]){
				callBackArr = self.callbackObj.rejectCallBack;
			}else{
				callBackArr = [self.callbackObj.catchCallBack];
			}
		}
		if(callBackArr&&callBackArr.length>0){
			callBackArr.forEach((item)=>{
				item&&item(self.data)
			})
		}
		if(self.callbackObj.finallyCallback){
			self.callbackObj.finallyCallback()
		}
	}
	function resolve(value) {//声明resolve方法，支持报成功
	   if(self.status === 'pending') {
		   self.status = 'resolved';
		   self.data = value;
		   self.doCallback()
	   }
	}
	function reject(value) {
	   if(self.status === 'pending') {
		   self.status = 'rejected';
		   self.data = value;
		   self.doCallback()
	   }
	}
	setTimeout(function(){
		callback&&callback(resolve,reject);
	})
}



//根据es6文档，此处的promise，原型链上需要增加一个.then方法，来支持调用结果后，执行的方法，此方法也接收一个回调函数
myPromise.prototype.then = function(resolveCallback,rejectCallBack){//.then存入待执行事件，不然如果是异步操作，则未完成时候.then就执行了
	this.callbackObj.resolveCallback?this.callbackObj.resolveCallback.push(resolveCallback):this.callbackObj.resolveCallback=[resolveCallback];
	this.callbackObj.rejectCallBack?this.callbackObj.rejectCallBack.push(rejectCallBack):this.callbackObj.rejectCallBack=[rejectCallBack];
	return this
}

myPromise.prototype.catch=function(catchCallBack){
	this.callbackObj.catchCallBack=catchCallBack;
}

myPromise.prototype.finally=function(finallyCallback){
	this.callbackObj.finallyCallback=finallyCallback;
}


myPromise.all = function(promiseArr=[]){
	let resultArr = [];//当前已完成的子promisedata结果
	return new myPromise((resolve)=>{
		promiseArr.forEach((item)=>{
			item.then((data)=>{
				resultArr.push(data);
				console.log(resultArr.length==promiseArr.length,100)
				if(resultArr.length==promiseArr.length){
					resolve(resultArr)
				}
			})
		})
	})
}


myPromise.race = function(promiseArr=[]){
	new myPromise((resolve)=>{
		promiseArr.forEach((item)=>{
			item.then((data)=>{
				resolve(data)
			})
		})
	})
}

myPromise.allSettled = function(promiseArr=[]){
	let resultArr = [];//当前已完成的子promisedata结果
	let okNum = 0;
	return new myPromise((resolve,reject)=>{
		function doCallBack(){//执行结果
			if(okNum==promiseArr.length){
				resolve(resultArr)
			}
		}
		promiseArr.forEach((item)=>{
			item.then((data)=>{
				resultArr.push({
					status:"fulfilled",
					value:data
				});
				okNum++;
				doCallBack()
			},(data)=>{
				resultArr.push({
					status:"rejected",
					value:data
				});
				okNum++;
				doCallBack()
			})
		})
	})
}

myPromise.any = function(promiseArr=[]) {
	return new myPromise((resolve,reject)=>{
		let resultArr = [];
		let okNum = 0;
		function doCallBack(){//执行结果
			if(okNum==promiseArr.length){
				reject(resultArr)
			}
		}
		promiseArr.forEach((item)=>{
			item.then((data)=>{
				this.status="fulfilled";
				resolve(data);
			},(data)=>{
				okNum++
				resultArr.push('reject')
			})
		})
	})
}

myPromise.resolve = function(data){
	return new myPromise((resolve)=>{
		resolve(data)
	})
	
}

myPromise.reject = function(data){
	return new myPromise((resolve,reject)=>{
		reject(data)
	})
}