Leetcode 2. Add Two Numbers - You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. You may assume the two numbers do not contain any leading zero, except the number 0 itself.

leetcode-2-sum-linked-lists.js

const addTwoLists = (l1, l2) => {
  let n1=0, n2=0, count=0;
  while(l1 !== null) {
    n1 += (l1.val)*Math.pow(10,count);
    l1 = l1.next;
    count++;
  }
  count=0;
  while(l2 !== null) {
    n2 += (l2.val)*Math.pow(10,count);
    l2 = l2.next;
    count++;
  }
  return n1+n2;
};