Subscriptions Interview Questions

Subscriptions enable real-time data updates through WebSocket connection. Maintain live connection for event-based updates. Features: real-time data, event handling. Essential for live updates.

WebSocket setup through split network interface, protocol configuration. Configure connection parameters, authentication. Features: persistent connection, protocol handling. Enable real-time communication.

Subscription client manages WebSocket connections, subscription lifecycle. Handle connection states, message processing. Features: message queuing, reconnection logic. Manage subscription operations.

Subscription authentication through connection params, token validation. Implement secure WebSocket connection, session management. Features: token handling, connection security. Ensure secure subscriptions.

Subscription events through PubSub system, event filtering. Implement event triggers, data transformation. Features: event publishing, subscription filtering. Handle real-time updates.

Subscription cleanup through proper unsubscription, connection termination. Handle component unmount, cleanup effects. Features: resource management, memory cleanup. Prevent memory leaks.

Subscription variables through dynamic parameters, event filtering. Configure subscription behavior, data filtering. Features: dynamic subscriptions, parameter handling. Customize subscription data.

Subscription errors through error callbacks, connection recovery. Implement error handling, retry logic. Features: error reporting, connection management. Handle subscription failures.

Subscription link options through configuration parameters, connection settings. Configure timeout, reconnect attempts. Features: link customization, behavior control. Optimize subscription handling.

Subscription filtering through withFilter function, filter conditions. Implement data filtering, event selection. Features: selective updates, data relevance. Control update flow.

Payload transformation through resolvers, data mapping. Implement data formatting, structure conversion. Features: data shaping, response formatting. Customize subscription data.

Reconnection handling through retry policies, connection monitoring. Implement backoff strategy, state recovery. Features: connection resilience, session management. Maintain subscription stability.

Subscription contexts through context providers, data sharing. Share data across subscription resolvers. Features: context access, data availability. Enable shared subscription state.

Subscription testing through mock WebSocket, event simulation. Test subscription behavior, event handling. Features: connection testing, event verification. Ensure subscription reliability.

Best practices include proper cleanup, error handling, connection management. Implement efficient filtering, payload optimization. Features: performance consideration, resource management. Optimize subscription usage.