打乱数组排序

let arr = [1,2,3,4,5,6,7,8,9];
for (let i=0,len=arr.length;i<len;i++) {
    let currentRandom = parseInt(Math.random() * (len-1));
    let current = arr[i];
    arr[i] = arr[currentRandom];
    arr[currentRandom] = current;
}