palindrome.js

#!/usr/bin/env node

var str = process.argv[2].toString();

var palindromeCheck = function(str) {
  var palindrome = true,
    chars = {},
    allowance = false;

  if (str.length % 2 === 1) allowance = true;

  for (var i = 0, len = str.length; i < len; i++) {
    if (!chars[str[i]]) chars[str[i]] = 0;
    chars[str[i]] += 1;
  }

  for (var c in chars) {
    if (chars[c] % 2 !== 0) {
      if (allowance) {
        allowance = false;
      } else {
        palindrome = false;
      }
    }
  }

  if (palindrome) return 1;
  return 0;
};

console.log(palindromeCheck(str));