function* innerGenerator() {
  yield 1;
  yield 2;
  return 'inner-done';
}

function* outerGenerator() {
  yield 'start';
  const result = yield* innerGenerator();
  yield result;
  yield 'end';
}

const gen = outerGenerator();
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next().value);