reverseVowels.js

const reverseVowels = (word) => {
  if (typeof word !== 'string') return "Invalid Input Parameter";
  let start = 0;
  let end = word.length - 1;
  let vowels = {
    a: true,
    e: true,
    i: true,
    o: true,
    u: true,
    A: true,
    E: true,
    I: true,
    O: true,
    U: true,
  };
  let arrayOfLetter = [...word];

  while (start <= end) {
    let placeholder = null;
    if (vowels[arrayOfLetter[start]] && vowels[arrayOfLetter[end]]) {
      placeholder = arrayOfLetter[start];
      arrayOfLetter[start] = arrayOfLetter[end];
      arrayOfLetter[end] = placeholder;
      start++;
      end--;
    } else if (vowels[arrayOfLetter[start]] && !vowels[arrayOfLetter[end]]) {
      end--;
    } else if (vowels[arrayOfLetter[end]] && !vowels[arrayOfLetter[start]]) {
      start++;
    } else {
      start++;
      end--;
    }
  }
  return arrayOfLetter.join("");
};