iterators-ftw.js

// {
//   next: () -> { done: false, value: any }
//             | { done: true[, value: any] }
// }

var i1 = (function *f() {
  return;
})();

'value' in i1.next();

var i2 = (function *g() {
})();

'value' in i2.next();

var i3 = (function* h() {
  return (void 0);
})();

'value' in i3.next();