reverseVowelsInPlace

/*$
reverseVowels(word) - 
Given an array of characters, 
reverse the vowels but keep the consonants in place.

Space complexity: O(1)
Time complexity: O(N)

Example: ["w","h","i","t","e","b","o","a","r","d"] ->
         ["w","h","a","t","o","b","e","i","r","d"]

*/

const letters = ["w","h","i","t","e","b","o","a","r","d"];

function reverseVowels(word) {
  let vowels = /[aeiou]/
  let start = 0;
  let end = word.length - 1;
  let temp;
  

  while (start !== end) {
    if (!word[start].match(vowels) && !word[end].match(vowels)) {
      start += 1;
      end -= 1;
    }
    
    if (word[start].match(vowels) && !word[end].match(vowels)) {
      start += 1;
    }
    
    if (!word[start].match(vowels) && word[end].match(vowels)) {
      start += 1;
    }
    
        
    if (word[start].match(vowels) && word[end].match(vowels)) {
      temp = word[start];
      word[start] = word[end];
      word[end] = temp;
      start += 1;
      end -= 1;
    }
  }
  
  return word;  
}

console.log(reverseVowels(letters));