Answer 1

function f(arr,k){arr.unshift(...arr.splice(-k)); console.log(arr) }
var rotate = function (nums, k) {
nums.unshift(...nums.splice(nums.length - k, k))
return nums
};
function rotateArr(arr,k){
return[...arr.splice(-k), ...arr]
}

@kungithub
@kingstone3
@yupeilin123
@i-lijin
都试试下面这个case

f([1,2],13);
> [1, 2]

function rotateArr(arr, k) { 
  return [...arr.splice(-(k % arr.length)), ...arr];
}