[рони]

galiog,

let array = [
        [1, 2, 3],
        [4, 5, 6],
        [7, 8, 9]
    ],
    [a, b, i, j, l] = [0, 1, 0, 0, 9],
    arr = [];
for (let k = 0; k < l; k++) {
    let v = array[i] && array[i][j];
    if (v && !arr.includes(v)) {
        arr.unshift(v);
    } else {
        k--;
        i -= a;
        j -= b;
        [a, b] = a ? [b, -a] : [b, a]
    };
    i += a;
    j += b;
}
console.log(arr)
alert(arr)