User Identification

Event: button_clicked
Event: page_viewed
Event: purchase_made

User user_123:
  → button_clicked
  → page_viewed
  → purchase_made

// When user logs in
grain.setUserId('user_123');

// All these events now belong to user_123
grain.track('dashboard_viewed');
grain.track('report_generated');
grain.track('settings_updated');

// These are equivalent
grain.identify('user_123');
grain.setUserId('user_123');

const userId = grain.getUserId();

if (userId) {
  console.log(`Tracking as user: ${userId}`);
} else {
  console.log('Anonymous tracking');
}

const grain = createGrainAnalytics({
  tenantId: 'your-tenant-id',
  userId: 'user_123'
});

// Events immediately track with this user ID
grain.track('app_opened');

// User logs out
grain.setUserId(null);

// Events are now anonymous
grain.track('logged_out');

// On app load, restore user from your auth system
const currentUser = getCurrentUser(); // Your auth logic

if (currentUser) {
  grain.setUserId(currentUser.id);
}

// ✅ Good: Stable user ID
grain.setUserId('user_8f3a2c1b');

// ❌ Bad: Email might change
grain.setUserId('user@example.com');

// ❌ Bad: Session ID changes every session
grain.setUserId('session_xyz123');

// React example
function App() {
  const { user } = useAuth();

  useEffect(() => {
    if (user) {
      grain.setUserId(user.id);
    } else {
      grain.setUserId(null);
    }
  }, [user]);

  // ... rest of app
}

// Identify user
grain.setUserId('user_123');

// Add properties
await grain.setProperty({
  plan: 'premium',
  signup_date: '2024-01-15'
});

// Anonymous tracking
grain.track('landing_page_viewed');
grain.track('signup_button_clicked');

// User signs up - now identify them
grain.setUserId('user_123');

// Identified tracking
grain.track('account_created');

// API route handler
app.post('/api/action', async (req, res) => {
  const userId = req.user.id;
  
  grain.setUserId(userId);
  await grain.track('api_action_performed', {
    endpoint: '/api/action'
  }, { flush: true });
  
  // ... handle request
});

// Serverless function
export async function handler(event) {
  const grain = createGrainAnalytics({
    tenantId: 'your-tenant-id',
    userId: event.userId
  });

  await grain.track('function_executed', {}, { flush: true });
  
  return { statusCode: 200 };
}

import { GrainProvider } from '@grainql/analytics-web/react';

function App() {
  const { user } = useAuth();

  return (
    <GrainProvider 
      config={{ 
        tenantId: 'your-tenant-id',
        userId: user?.id  // Updates automatically when user changes
      }}
    >
      <YourApp />
    </GrainProvider>
  );
}