title: Reverse vowels in a string, using regex
body: <p>I am working on an algorithm that takes in a string for input, and reverses the vowels of the string.</p>
  
  <ul>
  <li>'hello' should return as 'holle' </li>
  <li>'wookiE' should return as 'wEikoo'</li>
  </ul>
  
  <p>Could <code>str.replace</code> be used as a solution?</p>
  
  <pre><code>function reverseVowels(str) {
      return str.replace(/[aeiou]/-g, /[aeiou]+1/);
  }
  </code></pre>
  
  <p>I am not sure what the second parameter for the <code>replace</code> function would be. I intended to find the first vowel and then move on to the next one to replace it with. Can this be done just with this method or is a <code>forEach</code>/<code>for</code> loop needed?</p>