checkiflinkedlistispalindrome.js

function isPalindrome(head) {
  let arr = [];
  let current = head;

  while (current) {
    arr.push(current.val);
    current = current.next;
  }

  let i = 0;
  let j = arr.length - 1;

  while (i < j) {
    if (arr[i] !== arr[j]) {
      return false;
    }
    i++;
    j--;
  }

  return true;
}