Is Palindrome

How is 'Is Palindrome' Asked?

Given a string, return true if the string is a palindrome or false if it is not.

• palindrome("madam") === true
• palindrome("abcdefg") === false
• palindrome("racecar")

Is Palindrome Questions to Ask

• What is considered a palindrome?
• What about strings that contain spaces, casing, special characters?
• Could I use built-in methods?

How to detect Palindrome?

Is Palindrome Pseudocode

// function that accepts a string
// clean the string if needed
// reverse the string in some way
// compare reversed version to original

Javascript Is Palindrome

function isPalindrome(string) {
  // string manipulation if needed to lowercase
  string = string.toLowerCase();
  var charactersArray = string.split('');

  //  string manipulation if needed remove non a-z characters
  var validCharacters = 'abcdefghijklmnopqrstuvwxyz'.split('');
  var lettersArray = [];
  charactersArray.forEach((char) => {
    if (validCharacters.indexOf(char) > -1) {
      lettersArray.push(char);
    }
  });

  // -----------------------
  // THIS IS WHAT MATTERS
  // -----------------------
  // if letters in reverse match original letters
  if (lettersArray.join('') === lettersArray.reverse().join('')) {
    // return true for yes it isPalindrome
    return true;
  } else {
    // else it's not a palindrome
    return false;
  }
}

isPalindrome("Madam I'm Adam"); // $: true
isPalindrome("Madam I'm Adams"); // $: false

Additional Is Palindrome Resources

• Algorithm: Palindrome