You probobly don't need a helper library for Promise/Async a

// You probobly don't need a helper library for Promise/Async after all
const seedValues = [Promise.resolve(777), Promise.resolve(888)];

// reduce
// Promise based
seedValues
  .reduce((accumulator, currentValue) =>
    accumulator.then(v => currentValue.then(cv => v + cv))
  )
  .then(console.log.bind(console));

// async
seedValues
  .reduce(async (acc, c) => (await acc) + (await c))
  .then(console.log.bind(console));

// simple map
// Promise based
Promise.all(seedValues.map(p => p.then(v => v.toString()))).then(
  console.log.bind(console)
);

// async
Promise.all(seedValues.map(async p => (await p).toString())).then(
  console.log.bind(console)
);