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The SDK detects maintenance mode reactively via 503 responses. Write operations are blocked; reads are still allowed.

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Event Handlers

The simplest way to handle maintenance is via constructor callbacks: 
const sdk = new HaspSDK({
  onMaintenanceStart: (status) => {
    document.getElementById('maintenance-banner').style.display = 'block';
    document.getElementById('maintenance-message').textContent =
      status.message ?? 'App is being updated.';
  },
  onMaintenanceEnd: () => {
    document.getElementById('maintenance-banner').style.display = 'none';
  },
});
Or attach/remove handlers dynamically: 
// sdk.on() returns an unsubscribe function
const unsubStart = sdk.on('maintenanceStart', (status) => { /* ... */ });
const unsubEnd   = sdk.on('maintenanceEnd', () => { /* ... */ });

// Remove later:
unsubStart();
unsubEnd();

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Write Behavior

Write operations throw MaintenanceError immediately if the SDK is already in maintenance state — they do not hit the server: 
try {
  await sdk.createRecord('tasks', data);
} catch (error) {
  if (error instanceof HaspSDK.MaintenanceError) {
    showMessage('App is being updated. Please try again shortly.');
  }
}

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Read Behavior

Read operations (listRecords, getRecord, paginateRecords, getSchema, getBootstrap) are allowed during maintenance and may succeed depending on server behavior.

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Automatic Recovery

Maintenance mode clears automatically — if any request succeeds after a 503, the SDK exits maintenance mode and fires maintenanceEnd.

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Proactive Detection

The SDK only detects maintenance reactively. For proactive detection before a write fails, implement your own status poller: 
const poller = setInterval(async () => {
  const status = await sdk.getStatus();
  if (status.status === 'maintenance') {
    showMaintenanceBanner(status.message);
  } else {
    hideMaintenanceBanner();
  }
}, 15_000);

clearInterval(poller);
sdk.destroy();

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getStatus(signal?)

Fetches the current app status without triggering maintenance mode detection. 
const status = await sdk.getStatus();
// status.status           — 'ok' | 'maintenance'
// status.message          — optional human-readable message
// status.estimatedSeconds — optional estimated downtime in seconds