A Common-Sense Guide to Data Structures and Algorithms, Second Edition, 2nd Edition

Palindrome Checker

A palindrome is a word or phrase that reads the same both forward and backward. Some examples include “racecar,” “kayak,” and “deified.”

Here’s a JavaScript function that determines whether a string is a palindrome:

function isPalindrome(string) {

  // Start the leftIndex at index 0:
  let leftIndex = 0;
  // Start rightIndex at last index of array:
  let rightIndex = string.length - 1;

  // Iterate until leftIndex reaches the middle of the array:
  while (leftIndex < string.length / 2) {

    // If the character on the left doesn't equal the character
    // on the right, the string is not a palindrome:
    if (string[leftIndex] !== string[rightIndex]) {
      return false;
    }

    // Move leftIndex one ...