Print the fibonacci series till the nth sequence. Use memoization. (JavaScript solution)

fibonacci.js

//Normal fibonacci - No Memoization
//Fib series - 1 1 2 3 5 8 13 21 34 ...
//O(2^n) = exponential time complexity
function fib(n) {
  if(n <= 2) {
    return 1;
  }
  return fib(n-2) + fib(n-1);
}

//With Memoization
var arr = [1,1]; //capture the first 2 numbers of the sequence
function fib(n) {
  if(arr[n-1]) { //memoization
    return arr[n-1];
  } else {
    arr[n-1] = fib(n-2) + fib(n-1); //cache it
    return arr[n-1];
  }
}
console.log(arr.join(' '));

//Shorter form for Memoization
var arr = [1,1];
function fib(n) {
  return arr[n-1] || (arr[n-1] = fib(n-2) + fib(n-1));
}
console.log(arr.join(' '));