Promises to async/await

users.js

// original Promise-only version. I try to write my functions to be pure
// when appropriate so that they are composable in to promise chains like
// this
function findOrCreateUser(id /* :string */, user /* :User */) /* :Promise<User> */ {
  return db.users
    .hsetnx(id, 'created_at', user.created_at.toJSON())
    .then(function(isNew) {
      if (isNew) {
        logger.info({user: user}, 'New user');
        return db.users.hmset(id, serializeUser(user))
          .then(returnUser)
          .then(backfillUser)
          .then(newTokenForUser)
          .then(findUserByToken)
          .then(markAsNew);
      } else {
        logger.info({user: user}, 'Existing user');
        return db.users.hgetall(id)
          .then(deserializeUser)
          .then(backfillUser);
      }
    });
  function returnUser() {
    return user;
  }
  function markAsNew(user /* :User */) {
    user.isNew = true;
    return user;
  }
}

// First pass at converting the function from "just" Promises to using async and await
// Is this how async/await are supposed to be used?
async function findOrCreateUser(id /* :string */, user /* :User */) /* :Promise<User> */ {
  const isNew = await db.users.hsetnx(id, 'created_at', user.created_at.toJSON());
  if (isNew) {
    logger.info({user: user}, 'New user');
    await db.users.hmset(id, serializeUser(user));
    user = await backfillUser(user);
    const token = await newTokenForUser(user);
    user = await findUserByToken(token);
    user.isNew = true;
    return user;
  } else {
    logger.info({user: user}, 'Existing user');
    const serializedUser = await db.users.hgetall(id);
    return backfillUser(deserializeUser(serializedUser));
  }
}