Найдите конкретный символ в строке и измените его позицию на предыдущий символ, используя javascript, jquery

function switchChar(text, charToFind) {
  //temp variable for building result
  var result = "";
  //loop over original string
  for (var i = 0; i < text.length; i++) {
    //chack not to jump out of array
    if (i + 1 < text.length) {
      //if next char is the char im looking for 
      if (text[i + 1] == charToFind) {
        //write next char first
        result += charToFind;
        //then write original char
        result += text[i];
        //iterate i once more to jump over next char (I appended two chars in this single cycle)
        i++;
        //if it is not the char Im looking for
      } else {
        //write it down
        result += text[i];
      }
      //I am at the end
    } else {
      //write the char
      result += text[i];
    }
  }
  return result;
}

console.info(switchChar('Kù Iù Mù', 'ù'))