Comparing multiple Fibonacci iterators

fibonacci.ts

const fib = (n: number): number => n === 0 ? 0 : n === 1 ? 1 : (fib(n - 1) + fib(n - 2))

console.log(Array.from(Array(21).keys()).map(fib))

const fibgen = function* (n: number) {
    if (n < 0) throw RangeError("number cannot be negative")
    if (!Number.isInteger(n)) throw TypeError("number should be an integer")

    let first = 0, second = 1

    yield first

    if (n >= 1) yield second

    for (let tick = 2; tick <= n; tick++) {
        [first, second] = [second, first + second]
        yield second
    }
}

console.log([...fibgen(20)])

function fibArray(n: number) {
  const fib = [0, 1];
  for (let i = 2; i <= n; i++) {
    fib.push(fib[i - 1] + fib[i - 2]);
  }
  return fib;
}

console.log(fibArray(20))