async-await-patterns

async function operationName(): Promise<ReturnType> {
  try {
    const result = await asyncOperation();
    return result;
  } catch (error) {
    // Handle or rethrow with context
    throw error;
  }
}

// PARALLEL: independent operations
const [a, b, c] = await Promise.all([fetchA(), fetchB(), fetchC()]);

// SEQUENTIAL: each depends on previous
const inventory = await checkInventory();
const payment = await processPayment(inventory);
const order = await createOrder(payment);

// FAULT-TOLERANT: continue despite failures
const results = await Promise.allSettled([op1(), op2(), op3()]);

async function updateProfile(userId: string, updates: Updates): Promise<User> {
  try {
    const user = await database.users.findById(userId);
    if (!user) throw new Error(`User ${userId} not found`);

    const validated = await validateData(updates);
    const updated = await database.users.update(userId, validated);

    await Promise.all([
      notify(userId, 'Profile updated'),
      auditLog.record('profile_update', { userId })
    ]);

    return updated;
  } catch (error) {
    if (error instanceof ValidationError) throw new BadRequestError('Invalid data', error);
    if (error instanceof DatabaseError) throw new ServiceError('DB failed', error);
    throw error;
  }
}