1
var isToeplitzMatrix = function (matrix) {
2
  for (let i = 0; i < matrix.length - 1; i++) {
3
    for (let j = 0; j < matrix[i].length - 1; j++) {
4
      if (matrix[i][j] !== matrix[i + 1][j + 1]) {
5
        return false;
6
      }
7
    }
8
  }
9

10
  return true;
11
};