1function merge (L1, L2) {
2    let L3 = { data: null, next: null };
3    let prev = L3;
4
5    while (L1 != null || L2 != null) {
6        if (L1 === null) {
7            prev.next = L2;
8            L2 = L2.next;
9            continue;
10        }
11
12        if (L2 === null) {
13            prev.next = L1;
14            L1 = L1.next;
15            continue;
16        }
17
18        if (L1.data <= L2.data) {
19            prev.next = L1;
20            L1 = L1.next;
21        } else {
22            prev.next = L2;
23            L2 = L2.next;
24        }
25
26        prev = prev.next;
27    }
28
29    return L3.next;
30};
31