spiralMatrixRotate.js

/**
 * @param {number[][]} matrix
 * @return {number[][]} Indexes as an array of (row, col) tuples.
 */
const spiralOrder = (matrix) => {
  let indexes = [];

  const width = matrix[0].length;
  const height = matrix.length;

  for (let ring = 0; ; ring++) {
    const wEnd = width - 1 - ring;
    const hEnd = height - 1 - ring;

    if (ring > wEnd || ring > hEnd) break;

    // Top
    for (let i = ring; i <= wEnd; i++) indexes.push([ring, i]);

    // Right
    for (let i = ring + 1; i <= hEnd; i++) indexes.push([i, wEnd]);

    // Bottom
    if (hEnd != ring)
      for (let i = wEnd - 1; i >= ring; i--) indexes.push([hEnd, i]);

    // Left
    if (ring != wEnd)
      for (let i = hEnd - 1; i > ring; i--) indexes.push([i, ring]);
  }

  return indexes;
};

/**
 * @param {number[]} matrix
 * @param {number} k
 */
const spiralRotate = (matrix, k) => {
  const so = spiralOrder(matrix);

  let counter = 0;

  for (let i = 0; i < so.length && counter < so.length; i++) {
    let temp = matrix[so[i][0]][so[i][1]];

    for (let j = i; ; ) {
      const offset = (j + k) % so.length;

      const tempCandidate = matrix[so[offset][0]][so[offset][1]];
      matrix[so[offset][0]][so[offset][1]] = temp;
      temp = tempCandidate;

      counter++;

      j = offset;
      if (j == i) break;
    }
  }
};

// Main

let matrix = [
  [1, 2, 3],
  [8, 9, 4],
  [7, 6, 5],
];

spiralRotate(matrix, 1);

// matrix:
//  [
//   [9, 1, 2],
//   [7, 8, 3],
//   [6, 5, 4],
// ];

console.log(JSON.stringify(matrix));