palindromePermutation.js

/// Palindrome Permutation: Given a string, write a function to
/// check if it is a permutation of a palin - drome.A palindrome
///  is a word or phrase that is the same forwards and backwards.A
/// permutation is a rearrangement of letters.The palindrome does not
/// need to be limited to just dictionary words.

function checkPalindromPermutation2(word) {
  const letterCount = new Map();
  for (let letter of word) {
    if (letterCount.has(letter)) {
      letterCount.set(letter, letterCount.get(letter) + 1);
    } else {
      letterCount.set(letter, 1);
    }
  }

  let oddCount = 0;
  letterCount.forEach((value, key) => {
    if (value % 2 != 0) {
      oddCount++;
    }
  });

  return oddCount <= 1;
}

function checkPalindromPermutation(word) {
  const letters = word.split("");
  const mappedLetters = new Map();

  for (var letter of letters) {
    if (letter != "" && mappedLetters.has(letter)) {
      mappedLetters.set(letter, mappedLetters.get(letter) + 1);
    } else {
      mappedLetters.set(letter, 1);
    }
  }

  let odd = 0;

  for (var mappedLetter of mappedLetters) {
    if (letter != "" && mappedLetters.get(letter) % 2 != 0) {
      odd++;
    }

    if (odd > 1) {
      return false;
    }
  }

  return true;
}

console.log(checkPalindromPermutation2("tot"));
console.log(checkPalindromPermutation2("car"));