Javascript Palindromes of Anagrams

palindrome-finder.js

/**
 * Returns `true` if any of the given string contains a palindrome.
 * @param {String} s the string to test
 */
function PalindromeFinder(s) {
  //build an array of characters from the string `s`
  var chars = s.split('');

  //store how many of the same char within the string (so the array)
  var charsOccurences = {};
  chars.forEach(function(c) {
    if (charsOccurences[c] === undefined) { //create if new
      charsOccurences[c] = 1; 
    } else { //increment
      charsOccurences[c] = charsOccurences[c] + 1; 
    }
  });

  var evens = 0; //count the evens
  var odds = 0; //count the odds

  for (var char in charsOccurences) {
    var occurrs = charsOccurences[char];
    if (occurrs % 2 === 0) { //count evens...
      evens = evens + 1;
    } else { //count odds...
      odds = odds + 1;
    }
  }

  //the result: 
  //  if the string length is even then `no odds chars can be present`
  //  if the string length is odd, then `JUST only one odd char can be found`.
  var result = false;
  if (s.length % 2 === 0) {
    if (odds === 0) { //no odds here please...
      result = true;
    }
  } else {
    if (odds === 1) { //here we want only one odd
      result = true;
    }
  }
  return result;
}

var isPaindrome = function (str) {
    str = str.toLowerCase().replace(/[^\w]/g, '');
    const length = str.length;
    var pivot = Math.floor(length / 2);
    for (let i = length - 1; i > pivot; i--) {
        let positionTail = i;
        let positionHead = (length - 1) - i;
        let charFromTail = str[positionTail];
        let charFromHead = str[positionHead];
        if (charFromTail !== charFromHead) {
            // console.log(`${charFromTail}@${positionTail} - ${charFromHead}@${positionHead}`);
            return false;
        }
    }
    return true;
}

console.log('test', 'ispal', 'str');
console.log('----', '-----', '----');
console.log(isPaindrome('a') === true,
            isPaindrome('a'),
            'a');
console.log(isPaindrome('aa') === true,
            isPaindrome('aa'),
            'aa');
console.log(isPaindrome('aba') === true,
            isPaindrome('aba'),
            'aba');
console.log(isPaindrome('ab') === true,
            isPaindrome('ab'),
            'ab');
console.log(isPaindrome('abc') === false,
            isPaindrome('abc'),
            'abc');
console.log(isPaindrome('123a321') === true,
            isPaindrome('123a321'),
            '123a321');
console.log(isPaindrome('123321') === true,
            isPaindrome('123321'),
            '123321');
console.log(isPaindrome('11a11') === true,
            isPaindrome('11a11'),
            '11a11');
console.log(isPaindrome('1234567890a0987654321') === true,
            isPaindrome('1234567890a0987654321'),
            '1234567890a0987654321');
console.log(isPaindrome('a;dfk43kl4') === false,
            isPaindrome('a;dfk43kl4'),
            'a;dfk43kl4');
console.log(isPaindrome('4577kddk223k5') === false,
            isPaindrome('4577kddk223k5'),
            '4577kddk223k5');
console.log(isPaindrome('A man a plan a canal Panama') === true,
            isPaindrome('A man a plan a canal Panama'),
            'A man a plan a canal Panama');
console.log(isPaindrome('Madam In Eden, I’m Adam') === true,
            isPaindrome('Madam In Eden, I’m Adam'),
            'Madam In Eden, I’m Adam');
console.log(isPaindrome('Mr. Owl Ate My Metal Worm') === true,
            isPaindrome('Mr. Owl Ate My Metal Worm'),
            'Mr. Owl Ate My Metal Worm');
console.log(isPaindrome('A Santa Lived As a Devil At NASA') === true,
            isPaindrome('A Santa Lived As a Devil At NASA'),
            'A Santa Lived As a Devil At NASA');
console.log(isPaindrome('Dammit, I’m Mad!') === true,
            isPaindrome('Dammit, I’m Mad!'),
            'Dammit, I’m Mad!');
console.log(isPaindrome('Was It A Rat I Saw') === true,
            isPaindrome('Was It A Rat I Saw'),
            'Was It A Rat I Saw');
console.log(isPaindrome('Do Geese See God?') === true,
            isPaindrome('Do Geese See God?'),
            'Do Geese See God?');