Why this linked list code is not working in my VSO?

Question

I am trying to learn linked list.I am learning from other people code. What I am trying to do is I am trying to console.log in many places. But the thing is the code does not work in my VSO.

Here is code working in leet code but not in my VSO.Why?

 //* Definition for singly-linked list.
  function ListNode(val, next) {
      this.val = (val===undefined ? 0 : val)
      this.next = (next===undefined ? null : next)
/**
 * @param {ListNode} l1
 * @param {ListNode} l2
 * @return {ListNode}
 */

var addTwoNumbers = function(l1, l2) {
    
  var List = new ListNode(0);
    var head = List;
    var sum = 0;
    var carry = 0;

    while(l1!==null||l2!==null||sum>0){

        if(l1!==null){
            sum = sum + l1.val;
            l1 = l1.next;
        }
        if(l2!==null){
            sum = sum + l2.val;
            l2 = l2.next;
        }
        if(sum>=10){
            carry = 1;
            sum = sum - 10;
        }

        head.next = new ListNode(sum);
        head = head.next;

        sum = carry;
        carry = 0;

    }

    return List.next;
};

addTwoNumbers([2, 4, 3], [5, 6, 4]);