palindromePermutation.js

function palindromePermutation(inputString) {
  // create a set to track characters we've seen
  const charSet = new Set();
  
  // iterate over each character by spitting into an array
  inputString.split('').forEach(char => {
    
    // remove from set if previously added
    if (charSet.has(char)) {
      charSet.delete(char);
      
    // add to set if not already present in set
    } else {
      charSet.add(char)
    }
  })

  // set should have 0 or 1 entry if is a palindrome
  return charSet.size <= 1;
}