1function rotateArray(A, K) {
2    if (!A.length) return A;
3    let index = -1;
4    while (++index < K) {
5        A.unshift(A.pop());
6    }
7    return A;
8}
9
10[
11    rotateArray([3, 8, 9, 7, 6], 3),
12    rotateArray([0, 0, 0], 1),
13    rotateArray([1, 2, 3, 4], 4),
14    rotateArray([], 4),
15].join(' | ');