AIでも壊れない堅牢コードへ鍛え直す！
コードレビュー道場 #3：非機能要件

async function getFeatureFlags() {
  const res = await fetch('https://flags.example.com/config.json');
  return res.json();
}

async function sendNotification(payload) {
  while (true) {
    try {
      await fetch('https://api.example.com/notify', {
        method: 'POST',
        body: JSON.stringify(payload)
      });
      return;
    } catch (e) {
      // 失敗したらリトライ
    }
  }
}

async function listOrdersWithUser(db) {
  const orders = await db.query('SELECT * FROM orders');
  for (const order of orders) {
    const rows = await db.query(
      'SELECT * FROM users WHERE id = ?',
      [order.user_id]
    );
    order.user = rows[0] ?? null;
  }
  return orders;
}

let currentCount = 0;

async function handleRequest(req, res) {
  currentCount++;
  // いろいろな処理...
  res.end('count: ' + currentCount);
}

function getConfig() {
  const raw = localStorage.getItem('config');
  return raw ? JSON.parse(raw) : {};
}

const logs = [];

function logEvent(event) {
  logs.push({
    at: new Date().toISOString(),
    event
  });
}

async function updateStatuses(users) {
  for (const user of users) {
    await fetch('/api/status', {
      method: 'POST',
      body: JSON.stringify({ id: user.id, status: 'active' })
    });
  }
}

async function handler(req, res) {
  try {
    const data = await loadFromDb();
    res.end(JSON.stringify(data));
  } catch (e) {
    res.statusCode = 404;
    res.end('Not found');
  }
}

async function fetchProfile(userId) {
  const res = await fetch(`https://api.example.com/users/${userId}`);
  if (!res.ok) {
    throw new Error('failed');
  }
  return res.json();
}

function processItem(item) {
  console.log('START PROCESS', item);
  doHeavyWork(item);
  console.log('END PROCESS', item);
}