How to rotate a matrix in JavaScript

JavaScript, algorithms, arrays, matrices

Here is one way of rotating a matrix in-place using JavaScript.
Space complexity: O(1).
Time complexity: O(n^2).

rotateMatrixTry in REPL
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function rotate(matrix, rotateCounterClockwise=false) {
  rotateClockwise = !rotateCounterClockwise;
  
  if (matrix.length === 0 || matrix.length !== matrix[0].length) return false;
  const n = matrix.length;
  for (let layer = 0; layer < Math.floor(n / 2); layer++) {
    const first = layer;
    const last = n - 1 - layer;
    for (let i = first; i < last; i++) {
      const offset = i - first;
      
      if (rotateClockwise) {
        const top = matrix[first][i]
        
        // left -> top
        matrix[first][i] = matrix[last-offset][first];
        
        // bottom -> left
        matrix[last-offset][first] = matrix[last][last-offset];
        
        // right -> bottom
        matrix[last][last-offset] = matrix[i][last];
        
        // top -> right
        matrix[i][last] = top; // right <- saved top
      } else if (rotateCounterClockwise) {
        const left = matrix[last-offset][first];
        
        // top -> left
        matrix[last-offset][first] = matrix[first][i]
        
        // right -> top
        matrix[first][i] = matrix[i][last];
        
        // bottom -> right
        matrix[i][last] = matrix[last][last-offset];
        
        // left -> bottom
        matrix[last][last-offset] = left;
      }
    }
  }
  return matrix;
}
function geometricRotate(matrix, rotateCounterClockwise=false) {
  if (matrix.length === 0 || matrix.length !== matrix[0].length) return false;
  rotateClockwise = !rotateCounterClockwise;
  
  if (rotateClockwise) {
    transpose(matrix)
    reverseRows(matrix);
  } else if (rotateCounterClockwise) {
    reverseRows(matrix)
    transpose(matrix);
  }
  return matrix;
}
function transpose(matrix) {
  for (let i = 0; i < matrix.length; i++) {
    for (j = 0; j < i; j++) {
      [matrix[i][j], matrix[j][i]] = [matrix[j][i], matrix[i][j]]; // swap values
    }
  }
}
function reverseRows(matrix) {
  for (let i = 0; i < matrix.length; i++) {
    const row = matrix[i];
    row.reverse();
  }
}
rotate = geometricRotate;

Tests can be found at REPL.it