recursive, non-recursive fibonacci

fibo.js

function fibo(n) {
  if (n < 2) return 1;

  var prev1 = 1, prev2 = 1, i = 2, current = 0;
  while (i <= n) {
    current = prev1 + prev2;
    prev2 = prev1;
    prev1 = current;
    i++;
  }
  return current;
}

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

var i = 0;

console.time("fibo");
for (i=1; i<=40; i++) {
  fibo(i);
}
console.timeEnd("fibo");

console.time("recursiveFibo");
for (i=1; i<=40; i++) {
  recursiveFibo(i);
}
console.timeEnd("recursiveFibo");

fibo: 0ms
recursiveFibo: 7976ms