Computes the transpose of a matrix represented by a 2-dimensional array

matrix_transpose.js

function transpose(mat){
  return mat[0].map((_, y) => {
    return mat.map((_, x) => {
      return mat[x][y];
    });
  });
}

var mat0 = [
  [0, 1, 2, 3, 4],
  [5, 6, 7, 8, 9],
];

transpose(mat0);
// [
//   [0, 5],
//   [1, 6],
//   [2, 7],
//   [3, 8],
//   [4, 9],
// ]