What is Cancellable?
A Cancellable in Combine is an object that controls the lifecycle of a subscription.
It allows you to stop receiving updates when you no longer need them, preventing memory leaks.
Think of it like a Netflix subscription:
- As long as you are subscribed, you keep getting to watch Netflix.
- If you cancel, the publisher stops access to Netflix.
- If you forget to cancel, you might keep access to Netflix but also will continue paying for that subscription.
Cancellable objects help manage memory by stopping subscriptions when they’re no longer needed.
🔗 Official Docs: Apple Documentation
How Cancellable Works
- Created when a subscriber subscribes to a publisher.
- Holds the subscription until canceled.
- Prevents memory leaks by stopping updates when not needed.
Example: Stopping a Subscription
import Combine
let publisher = ["Breaking News", "Swift 6 Released"].publisher
let cancellable = publisher
.sink { print("📢 Subscriber received: \($0)") }
// Stop receiving updates
cancellable.cancel()