Comparing times of getting fibonacci number with different method

fiboFasto.js

function fibo(n) {
  if (n <= 1) return n;
  return fibo(n-1) + fibo(n-2);
}

function tailFibo(n, tail) {
  if (n <= 1) return n;
  if (tail[n]) return tail[n];
  
  tail[n] = tailFibo(n-1, tail) + tailFibo(n-2, tail);
  return tail[n];
}

function itrFibo(n) {
  var prev = 0, cur = 1, total = 0, temp;
  while(n--) {
    prev = cur;
    temp = total;
    total += cur;
    cur = temp;
  }
  return total;
}

function testAllThree(n) {
  var results = {}, time;
  
  time = Date.now();
  fibo(n);
  results.fibo = Date.now() - time;
  
  time = Date.now();
  tailFibo(n, {});
  results.tailFibo = Date.now() - time;
  
  time = Date.now();
  itrFibo(n);
  results.itrFibo = Date.now() - time;
  return results;
}

testAllThree(30);