freeCodeCamp: Check for Palindromes

Return true if the given string is a palindrome. Otherwise, return false.

A palindrome is a word or sentence that’s spelled the same way both forward and backward, ignoring punctuation, case, and spacing.

Note
You’ll need to remove all non-alphanumeric characters (punctuation, spaces and symbols) and turn everything lower case in order to check for palindromes.

We’ll pass strings with varying formats, such as “racecar”,”RaceCar”, and “race CAR” among others.

We’ll also pass strings with special symbols, such as “2A3*3a2”,”2A3 3a2", and “2_A3*3#A2”.

Remember to use Read-Search-Ask if you get stuck. Write your own code.

Here are some helpful links:

• String.prototype.replace()
• String.prototype.toLowerCase()

Starting Code:

function palindrome(str) {
  // Good luck!
  return true;
}
palindrome("eye");

Use Cases:

palindrome("eye") should return a boolean.
palindrome("eye") should return true.
palindrome("_eye") should return true.
palindrome("race car") should return true.
palindrome("not a palindrome") should return false.
palindrome("A man, a plan, a canal. Panama") should return true.
palindrome("never odd or even") should return true.
palindrome("nope") should return false.
palindrome("almostomla") should return false.
palindrome("My age is 0, 0 si ega ym.") should return true.
palindrome("1 eye for of 1 eye.") should return false.
palindrome("0_0 (: /-\ :) 0-0") should return true.
palindrome("five|\_/|four") should return false.

Solution:

function palindrome(str) {
  
  str = str.toLowerCase();  //Turn everything to lower case
  // Remove all alphanumeric characters.
  str = str.replace(/[^a-z0-9]/g, '');

  var backward = str.split('');
  backward = backward.reverse().join('').toString();
  
  if(backward === str){
    return true;
  } else {
    return false;
  }
}