1290-convert-binary-number-in-a-linked-list-to-integer.js

/**
 * 1290. Convert Binary Number in a Linked List to Integer
 * https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer/
 * Difficulty: Easy
 *
 * Given `head` which is a reference node to a singly-linked list.
 * The value of each node in the linked list is either 0 or 1.
 * The linked list holds the binary representation of a number.
 * Return the decimal value of the number in the linked list.
 */

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} head
 * @return {number}
 */
var getDecimalValue = function(head) {
  let binary = String(head.val);

  while (head.next !== null) {
    head = head.next;
    binary += head.val;
  }

  return parseInt(binary, 2);
};