An elegant expression of the Fibonacci Sequence using generators https://en.wikipedia.org/wiki/Fibonacci_number

fb.es6

function * zipWith (zipper, ...iterables) {
  const iterators = iterables.map(i => i[Symbol.iterator]());

  while (true) {
    const pairs = iterators.map(j => j.next()),
          dones = pairs.map(p => p.done),
          values = pairs.map(p => p.value);

    if (dones.indexOf(true) >= 0) break;
    yield zipper(...values);
  }
};

function * tail (iterable) {
  const iterator = iterable[Symbol.iterator]();

  iterator.next();
  yield * iterator;
}

const plus = (x, y) => x + y;

function * fibs () {
  yield 0;
  yield 1;
  yield * zipWith(plus, fibs(), tail(fibs()));
}

fibs()
  //=> 0,1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2584,4181, ...

function memoize (generator) {
  const memos = {},
        iterators = {};
  
  return function * (...args) {
    const key = JSON.stringify(args);
    let i = 0;
    
    if (memos[key] == null) {
      memos[key] = [];
      iterators[key] = generator(...args);
    }
    
    while (true) {
      if (i < memos[key].length) {
        yield memos[key][i++];
      }
      else {
        const { done, value } = iterators[key].next();
        
        if (done) {
          return;
        } else {
          yield memos[key][i++] = value;
        }
      }
    }
  }
}

const mfibs = memoize(function * () {
  yield 0;
  yield 1;
  yield * zipWith(plus, mfibs(), tail(mfibs()));
});

mfibs()
  //=> 0,1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2584,4181, ...

It's even more elegant if you use lazy sequences and don't have to create exponentially many generator instances. :-)

It's even more elegant if you use lazy sequences and don't have to create exponentially many generator instances

Very true, I wanted to recreate the surface definition as directly as possible. I've added a memoized version (mfibs) for your entertainment.