Unsubscribing in GraphQL - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What happens when you unsubscribe from a GraphQL subscription?

In a GraphQL subscription, what is the expected behavior after a client unsubscribes?

A The server stops sending data updates to the client.

B The server continues sending data updates until the client reconnects.

C The client automatically reconnects and resubscribes.

D The server deletes all data related to the subscription.

💡 Hint

Think about what unsubscribing means in a real-life newsletter subscription.

Unsubscribing means the client no longer wants to receive updates, so the server stops sending data.

❓ query_result

intermediate

Identify the output after unsubscribing

Given a GraphQL subscription that sends live chat messages, what will the client receive after unsubscribing?

GraphQL

subscription {
  newMessage {
    id
    content
  }
}

// Client unsubscribes after receiving 3 messages

A All messages continue to be received.

B An error message indicating subscription ended.

C Only messages with id less than 3 are received.

D No more messages after the third one.

💡 Hint

Unsubscribing stops the flow of new data.

After unsubscribing, the client stops receiving any new messages.

📝 Syntax

advanced

Which code snippet correctly unsubscribes from a GraphQL subscription?

Select the code snippet that properly unsubscribes from a GraphQL subscription using JavaScript.

GraphQL

const subscription = client.subscribe({ query: NEW_MESSAGES });
// Unsubscribe code here

A client.unsubscribe(subscription);

B subscription.unsubscribe();

C subscription.stop();

D client.stopSubscription(subscription);

💡 Hint

Look for the method directly on the subscription object.

The unsubscribe() method is called on the subscription object to stop receiving updates.

❓ optimization

advanced

Optimizing resource usage after unsubscribing

Why is it important for the server to clean up resources after a client unsubscribes from a GraphQL subscription?

A To prevent memory leaks and reduce unnecessary processing.

B To keep the subscription active for faster reconnection.

C To send a confirmation message to the client.

D To archive the subscription data for analytics.

💡 Hint

Think about what happens if unused subscriptions stay active.

Cleaning up resources prevents the server from wasting memory and CPU on inactive subscriptions.

🔧 Debug

expert

Debugging why unsubscribing does not stop updates

A client unsubscribes from a GraphQL subscription but still receives updates. What is the most likely cause?

A The network connection is lost.

B The server does not support subscriptions.

C The unsubscribe method was not called correctly on the subscription object.

D The client is using a query instead of a subscription.

💡 Hint

Check how the client handles the subscription object.

If unsubscribe() is not called properly, the server keeps sending updates.