Diagonal Difference | Solution | JavaScript

Get the difference (sum)diagonals in the matrix on javascript.js

let arr = [
  [-1, 1, -7, -8],
  [-10, -8, -5, -2],
  [0, 9, 7, -1],
  [4, 4, -2, 1],
];
function diagonalDifference(arr) {
// Extraction of the primary diagonal
  let left = arr
    .map((e, i) => {
      return arr[i][i];
    })
    .reduce((acc, e) => acc + e);
//Extraction of the secondary diagonal.
    let right = arr
    .map((e, i) => {
      return arr[i][arr.length - i - 1];
    })
    .reduce((acc, e) => acc + e);
//difference
  let dif = left - right;
// return absolute difference value.
  return Math.abs(dif);
}

console.log(diagonalDifference(arr));