Fibonacci Recursive vs Iterative in JavaScript

// Given a number N return the index value of the Fibonacci sequence, where the sequence is:

// 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144 ...
// the pattern of the sequence is that each value is the sum of the 2 previous values, that means that for N=5 → 2+3

//For example: fibonacciRecursive(6) should return 8


// O(2^n)
function fibonacciRecursive(n) {
    if (n < 2) return n;
    let answer = fibonacciRecursive(n-1) + fibonacciRecursive(n-2);
  return answer;
}

// O(n)
function fibonacciIterative(n){
    let arr = [0, 1];
    for (let i=2; i<n + 1; i++)
    {
        arr.push(arr[i-2] + arr[i-1]);
    }
    return arr[n]
}


console.log(fibonacciRecursive(6));
console.log(fibonacciIterative(6));