How to check if a linked list is a palindrome in JavaScript

function isPalindrome(list) {
  const reversed = reverseAndClone(list);
  return isEqual(list, reversed);
}
function reverseAndClone(node) {
  let head = null;
  while (node) {
    const copy = new Node(node.data);
    copy.next = head;
    head = copy;
    node = node.next;
  }
  return head;
}
function isEqual(one, two) {
  while (one && two) {
    if (one.data !== two.data) {
      return false;
    }
    one = one.next;
    two = two.next;
  }
  return one === null && two === null;
}
// Uses a set to determine whether list is a palindrome
function isPalindromeAlternate(list) {
  const set = new Set();
  let current = list;
  while (current) {
    if (set.has(current.data)) {
      set.delete(current.data);
    } else {
      set.add(current.data);
    }
    current = current.next;
  }
  return set.size <= 1;
}
// Uncomment to use the alternate solution
// isPalindrome = isPalindromeAlternate;
function Node(data) {
  this.next = null;
  this.data = data;
}
Node.prototype.addToTail = function(data) {
  const end = new Node(data);
  let current = this;
  while (current.next !== null) {
    current = current.next;
  }
  current.next = end;
  return end;
};