1_4.js

module.exports = Strings1_4 = (function() {
  return{
    // Checks if a string is a permutation of a palindrome
    // Solution #4 from the book. Assumes ascii character set
    // @param {String} str - Word or phrase
    // @retuns {Boolean} - true if a permutation of palindrome exists, false if it does not
    palindromePermutation: function(str){
      var distinct = 0;
      var s_array = Array.apply(null, Array(256)).map(Number.prototype.valueOf, 0);
      str = str.toLowerCase();
      for(var i = 0; i < str.length; i++){
        if(str[i] == ' '){
          continue;
        }
        s_array[str[i].charCodeAt(0)]++;
        if(s_array[str[i].charCodeAt(0)] % 2){
          distinct++;
        }else{
          distinct--;
        }
      }
      return (distinct < 2);
    }
  };
}());