javascript recursion counter

Question

I tried to rewrite this indexOf MDN example to practice recursion

var str = 'To be, or not to be, that is the question.';
var count = 0;
var pos = str.indexOf('e');

while (pos !== -1) {
  count++;
  pos = str.indexOf('e', pos + 1);
}

console.log(count); // displays 4

This was my solution:

var count = 0;

function countLetters(str, p) {
  var pos = str.indexOf(p);
  if (pos == -1) {
    return count;
  }
  else {
    count ++;
    return countLetters(str.substr(pos + 1), p)
  }
}
console.log(countLetters('To be, or not to be, that is the question.', 'e'));

It works, but is there anyway to get the count variable inside the function itself? Is it not really a true recursion if I have a count variable outside the function?

Answer 1

What you can do is to return the count value form the method, so if the item is not found you return 0, else you return 1 + value-of-recursive-call

function countLetters(str, p) {
    var pos = str.indexOf(p);
    if (pos == -1) {
        return 0;
    } else {
        return 1 + countLetters(str.substr(pos + 1), p)
    }
}
console.log(countLetters('To be, or not to be, that is the question.', 'e'));

Demo: Fiddle