Comments that
write themselves.

async function cleanupExpired(sessions) {
  const now = Date.now();
  await Promise.all(
    sessions.map(async (s) => {
      if (s.expiresAt < now)
        await db.delete(s.id);
    })
  );
}

/**
 * Delete every session past its expiry.
 * @param {Session[]} sessions active set
 * @returns {Promise<void>} resolves once
 *   all stale rows are removed
 */
async function cleanupExpired(sessions) {
  const now = Date.now();
  // delete in parallel; await all
  await Promise.all(/* … */);
}