var doubleVowels = function (array) {
  var numVowels = 0;

  for (var i = 0; i < array.length; i++) {
    if (array[i] === 'a' || array[i] === 'e' || array[i] === 'i' || array[i] === 'o' || array[i] === 'u') {
      numVowels++;
    }
  }

  for (var i = array.length + numVowels - 1; i > 0; i--) {
    //i = 9 + 3 - 1 = 11
    array[i] = array[i - numVowels];

    if (array[i] === 'a' || array[i] === 'e' || array[i] === 'i' || array[i] === 'o' || array[i] === 'u') {
      numVowels--;
      i--;
      array[i] = array[i - numVowels];
    }
  }

  return array;
}