Remote day work - recursion and generators in Javascript

countdown.js

function countdown(n) {
  if (n >= 1) {
    console.log(n);
    countdown(n-1);
  }
}

countdown(5);

fibonacci.js

var i = 2;
var fib = [1, 1];

function fibonacci(n) {
  if (i < n) {
    fib[i] = fib[i-2] + fib[i-1];
    i++;
    fibonacci(n);
  } else {
    console.log(fib);
  }
}

fibonacci(10);

generator-factorial.js

function* factorialGenerator() {
  var count = 1;
  var i = 1;
  while (true) {
    if (count > 0) {
      i = i * count;
      count++;
    }
    yield i;
  }
}

var factorial = factorialGenerator();

console.log(factorial.next().value);
console.log(factorial.next().value);
console.log(factorial.next().value);
console.log(factorial.next().value);
console.log(factorial.next().value);