Can someone explain me what the code below means?

Question

function multiplyAll(arr) {
let product = 1;

for (var i = 0; i < arr.length; i++) {
for (var j = 0; j < arr[i].length; j++) {
product = product * arr[i][j];
}
}

return product;
}

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

Answer 1

It multiplies together each subarray and returns the product