Get transpose of a matrix. Worked with @Megwilken

matrix_transpose.js

const transpose = function (matrix) {
  let rows = matrix.length;
  let col = matrix[0].length;
  let transpose = [...Array(col)].map(row => Array(rows));
  for (let i = 0; i < rows; i++) {
    for (let j = 0; j < col; j++) {
      transpose[j][i] = matrix[i][j];
    }
  }
  return transpose;
};

// Do not edit this function.
const printMatrix = (matrix) => {
  for (const row of matrix) {
    for (const el of row) {
      process.stdout.write(el + " ");
    }
    process.stdout.write("\n");
  }
};

printMatrix(
  transpose([
    [1, 2, 3, 4],
    [1, 2, 3, 4],
    [1, 2, 3, 4],
    [1, 2, 3, 4],
  ])
);

console.log("----");

printMatrix(
  transpose([
    [1, 2],
    [3, 4],
    [5, 6],
  ])
);

console.log("----");

printMatrix(transpose([[1, 2, 3, 4, 5, 6, 7]]));