SOURCE

/**
 * 数组随机洗牌
 * @param  {Array} arr 
 * @returns Array
 */
function shuffle(arr) {
    var len = arr.length;
    for (var i = 0; i < len - 1; i++) {
        var idx = Math.floor(Math.random() * (len - i));
        var temp = arr[idx];
        arr[idx] = arr[len - i - 1];
        arr[len - i - 1] = temp;
    }
    return arr;
}
let arr=[1,2,3,4,5,6]
console.log(shuffle(arr))