promise all的实现

function promiseAll(Promises)
{
   return new Promise(function(resolve,reject){
     if(!Array.isArray(Promises))
     {
         return reject(new TypeError("argument"));
     }
     var countNum=0;
     var promiseNum=Promises.length;
     var resolvedvalue=new Array(promiseNum);
     for(let i=0;i<promiseNum;i++)
    {
        Promise.resolve(Promises[i]).then(function(value){
            countNum++;
            resolvedvalue[i]=value;
            if(countNum===promiseNum)
            {
                return resolve(resolvedvalue);
            }
        },function(reason){
            return reject(reason);
        })
    }
   })
}

var p1=Promise.resolve(1),
    p2=Promise.resolve(2),
    p3=Promise.resolve(3);
 
 promiseAll([p1,p2,p3]).then(function(value){
 	console.log(value)
 
 })