return-from-simple-spawn.js

const fromSpawn = spawn(function *() {
  const someVal = yield new Promise((res, rej) => {
    setTimeout(res.bind(null, 'whatevs!!!'), 5000);
  });
  
  console.log(someVal);
  return `I decided to return => ${someVal}`;
});

fromSpawn.then((data) => {
  console.log('Data from spawn', data);
}).catch((err) => {
  console.error('Err from spawn', err);
});