const arr = [
[1, 0, 2, 8],
[3, 5, 6, 9],
[7, 4, 1, 3]
];
const rows = arr.length;
const cols = arr[0].length;
let s = "";
for (let i = 0; i < rows; i++) {
for (let j = 0; j < cols; j++) {
s += arr[i][j] + " ";
}
console.log(s);
s = "";
}
/*
run:
"1 0 2 8 "
"3 5 6 9 "
"7 4 1 3 "
*/