Here is an example of a 3D array:
let arr = [
[
['a', 'b'],
['c', 'd'],
],
[
['e', 'f'],
['g', 'h'],
],
[
['i', 'j'],
['k', 'l'],
],
];
To display elements from such an array, you already need to write three square brackets pairs:
console.log(arr[0][0][0]); // shows 'a'
console.log(arr[2][1][0]); // shows 'k'
Given the following array:
let arr = [
[
[1, 2],
[3, 4],
],
[
[5, 6],
[7, 8],
],
];
Referring to each element of the array, find the sum of all its elements.