Fibonacci implementations in js

fibo.js

// implementation with Array
const fibo = len =>
  new Array(len).fill(1).reduce((acc, _, index) => {
    const value =
      index === 0 || index === 1
        ? index
        : acc[acc.length - 2] + acc[acc.length - 1];
    acc.push(value);
    return acc;
  }, []);

const fiboArray = fibo(10);
console.log(fiboArray); // [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]

// implementation with generators
function* fiboGen(len, current = 0, next = 1) {
  if (len === 0) {
    return current;
  }
  yield current;
  yield* fiboGen(len - 1, next, current + next);
}

const fiboGenerator = [...fiboGen(10)]
console.log(fiboGenerator) // [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]