Generators in js can do this ? omg o_0

generators_flow.js

function * fibo () {
  let a = 0, b = 1;
  while (true) {
    yield b;
    [a, b] = [b, a + b];
  }
}

function getIterable (iter) {
  return iter.next ? iter : iter();
}

function * filter(cb, generator) {
  const gen = getIterable(generator);
  for (let i of gen) {
    console.log(`filter ${i}`)
    if (cb(i)) {
      yield i
    }
  }
}

function * map(cb, generator) {
  const gen = getIterable(generator);
  for (let i of gen) {
      console.log(`map ${i}`);
      yield cb(i)
  }
}

function take(n, generator) {
    const g = generator.next ? generator : generator();
    const list = [];
    for (let i = 0; i < n; i++) {
      list.push(g.next().value)
    }
    return list;
  }

console.clear();

console.log(
  take(5, map(
    x => x + 1,
    filter(x => x % 2 === 0, fibo)
  ))
)


// "filter 1"
// "filter 1"
// "filter 2"
// "map 2"
// "filter 3"
// "filter 5"
// "filter 8"
// "map 8"
// "filter 13"
// "filter 21"
// "filter 34"
// "map 34"
// "filter 55"
// "filter 89"
// "filter 144"
// "map 144"
// "filter 233"
// "filter 377"
// "filter 610"
// "map 610"
// [3, 9, 35, 145, 611]

generators_flow_v2.js

function * fibo(upper_bound) {
  let a = 1, b = 1;
  
  while (b < upper_bound) {
    yield b;
    [a, b] = [b, a + b];
  }
};


Array.from(fibo(100));