Letter Changes code challenge day 6

function LetterChanges(str){
  // Firt get all the leters, global insensitive, then run a function that receives a char
  // Takes char, if it is z or Z change it to 'a'
  // Then convert to charCode and add 1. 
  let converted = str.replace(/[a-z]/gi, function(char){
    return(char === 'z'|| char ==='Z') ? 'a' : String.fromCharCode(char.charCodeAt() + 1);
  });
  // Find if the letter is a vowel the Upper Case it and replace it to the array.
  let capsVowel = converted.replace(/a|e|i|o|u/gi, function(vowel) {
    return vowel.toUpperCase();
  });

  return capsVowel;
}