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 contains a single digit. Add the two numbers and return the sum as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Example 1:

Input: l1 = [2,4,3], l2 = [5,6,4]
Output: [7,0,8]
Explanation: 342 + 465 = 807.

Example 2:

Input: l1 = [0], l2 = [0]
Output: [0]

Example 3:

Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]
Output: [8,9,9,9,0,0,0,1]

Constraints:

• The number of nodes in each linked list is in the range [1, 100].
• 0 <= Node.val <= 9
• It is guaranteed that the list represents a number that does not have leading zeros.

solution:

/**
 * 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) {
    let result = new ListNode();
    let aboveTen = 0;
    let arr = [];
    let currentNode1=l1 ;
    let currentNode2=l2;
    do {
        let a = 0;
        if(currentNode1 && currentNode1.val){
           a = currentNode1.val;
        }
        let b = 0;
        if(currentNode2 && currentNode2.val){
           b = currentNode2.val;
         }
         if(currentNode1){
           currentNode1 = currentNode1.next;
        }
        if(currentNode2){
           currentNode2 = currentNode2.next;
        }
        arr[arr.length]=(a+b+aboveTen)%10;
        aboveTen = (a+b+aboveTen)>=10?1:0;

    }while((currentNode1 && currentNode1.val!=null) || (currentNode2 && currentNode2.val!=null) );
    if(aboveTen>0){
       arr[arr.length]=aboveTen;
    }
    return generateNode(0,arr);
};

function generateNode(i, arr){
        if (i>=arr.length)
        {
            return null;
        }
        let node = new ListNode();
        node.val=arr[i];
        node.next = generateNode(++i,arr)
        return node;
}