手写Promise.all

// Promise.myAll(list)

Promise.myAll = function(list){
    let result = []
    let count = 0
    return new Promise(resolve,reject)=>{
        list.forEach(item,index)=>{
            item().then(res=>{
                result[index] = res
                count += 1
                if(count === list.lenght){
                    resolve(result)
                }
            },err=>{
                reject(err)
            })
        }
    }
}