Combine Framework
Publishers, subscribers, operators, subjects, backpressure, error handling, schedulers
1What is a Publisher in Combine?
What is a Publisher in Combine?
답변
A Publisher is a fundamental protocol in Combine that describes how a sequence of values can be delivered over time. It is responsible for emitting values or errors to subscribers that connect to it. Understanding this concept is essential for working with Combine, as all other framework elements depend on this publication model.
2What is a Subscriber in Combine?
What is a Subscriber in Combine?
답변
A Subscriber is a protocol that defines how to consume values emitted by a Publisher. It has three essential methods: receive(subscription:) to acknowledge the subscription, receive(_:) to handle values, and receive(completion:) to manage completion or errors. It is the receiving end of the data flow in Combine.
3Why should one store the AnyCancellable returned by subscribe()?
Why should one store the AnyCancellable returned by subscribe()?
답변
AnyCancellable is a token that keeps the subscriber alive. Without storing it in a property or variable, the object is immediately deallocated, canceling the subscription. This common mistake causes the data flow to stop immediately. Keeping AnyCancellable ensures the subscription remains active as long as needed.
What is the main role of an operator in Combine?
What is the difference between a Publisher and a Subscriber?
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