What will be the output of the following recursive function?

function removeDuplicates(str) {
  if (str.length <= 1) {
    return str;
  }
  let firstChar = str.charAt(0);
  let remainingStr = str.substr(1);
  if (remainingStr.includes(firstChar)) {
    return removeDuplicates(remainingStr);
  }
  return firstChar + removeDuplicates(remainingStr);
}
console.log(removeDuplicates("Hello World"));