let nums = [30,31,34,5,9]
//输出："9534330"


function compare(a, b) {
    let al = a.length;
    let bl = b.length;
    let l = al > bl ? al : bl;
    for (let i = 0; i < l; i++) {
　　　　// 此处重点 比较 3 与 31 的大小， 3要大于 31
        let av = a[i] || a[i-1]
        let bv = b[i] || b[i-1]
        if(av > bv){
            return 1
        }else if(av < bv){
            return -1
        }
    }
    return 0
}


function quicksort(arr){
    if(arr.length <= 1){
        return arr
    }
    let mid = Math.floor(arr.length/2)
    let midVal = arr.splice(mid,1)[0]
    let left =  [],right = []
    for(let i = 0; i< arr.length; i++){
        let iv = arr[i];
        console.log(midVal,iv,‘ivvvv‘)
        if(compare(midVal,iv) > 0){
            right.push(iv)
        }else{
            left.push(iv)
        }
    }
    return quicksort(left).concat([midVal]).concat(quicksort(right))

}

ret
let ret = quicksort(nums.map(item => item + ‘‘))
console.log(ret,‘ret‘)