Function isPalindromeIterative

String/IsPalindrome.js:19–37

(x)

*/

export function isPalindromeIterative(x) {
  if (typeof x !== 'string' && typeof x !== 'number') {
    throw new TypeError('Input must be a string or a number')
  }

  // Convert x to string whether it's number or string
  const string = x.toString()
  const length = string.length

  if (length === 1) return true

  // Apply two pointers technique to compare first and last elements on each iteration
  for (let start = 0, end = length - 1; start < end; start++, end--) {
    // Early return if compared items are different, input is not a palindrome
    if (string[start] !== string[end]) return false
  }
  // If early return in condition inside for loop is not reached, then input is palindrome
  return true
}