Recursive string reversal function in javascript?

One line of code using boolean operators.

Explanation: if string exists call the recursion to reduce the string, otherwise fallback to non existing string (last recursive call)

  function reverseString(s) {
    return s && reverseString(s.slice(1)) + s[0] || s;
  }

A tail recursive version, just for kicks (even though JavaScript doesn't perform tail call elimination):

function reverse(str) {
  function r(s, acc) {
    return (s.length == 0) ? acc : r(s.substr(1), s.charAt(0) + acc);
  };
  return r(str, '');
};

Something like:

function reverse (str) {
    if (str === "") {
        return "";
    } else {
        return reverse(str.substr(1)) + str.charAt(0);
    }
}

So the function is recursive as it calls itself to do the work.

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