# handleEvents(receiveSubscription:receiveOutput:receiveCompletion:receiveCancel:receiveRequest:) Performs the specified closures when publisher events occur. ``` func handleEvents(receiveSubscription: ((any Subscription) -> Void)? = nil, receiveOutput: ((Self.Output) -> Void)? = nil, receiveCompletion: ((Subscribers.Completion) -> Void)? = nil, receiveCancel: (() -> Void)? = nil, receiveRequest: ((Subscribers.Demand) -> Void)? = nil) -> Publishers.HandleEvents ``` ## Parameters `receiveSubscription` An optional closure that executes when the publisher receives the subscription from the upstream publisher. This value defaults to `nil`. `receiveOutput` An optional closure that executes when the publisher receives a value from the upstream publisher. This value defaults to `nil`. `receiveCompletion` An optional closure that executes when the upstream publisher finishes normally or terminates with an error. This value defaults to `nil`. `receiveCancel` An optional closure that executes when the downstream receiver cancels publishing. This value defaults to `nil`. `receiveRequest` An optional closure that executes when the publisher receives a request for more elements. This value defaults to `nil`. ## Return Value A publisher that performs the specified closures when publisher events occur. ## Discussion Use [`handleEvents(receiveSubscription:receiveOutput:receiveCompletion:receiveCancel:receiveRequest:)`](/documentation/Combine/Publisher/handleEvents(receiveSubscription:receiveOutput:receiveCompletion:receiveCancel:receiveRequest:)) when you want to examine elements as they progress through the stages of the publisher’s lifecycle. In the example below, a publisher of integers shows the effect of printing debugging information at each stage of the element-processing lifecycle: ``` let integers = (0...2) cancellable = integers.publisher .handleEvents(receiveSubscription: { subs in print("Subscription: \(subs.combineIdentifier)") }, receiveOutput: { anInt in print("in output handler, received \(anInt)") }, receiveCompletion: { _ in print("in completion handler") }, receiveCancel: { print("received cancel") }, receiveRequest: { (demand) in print("received demand: \(demand.description)") }) .sink { _ in return } // Prints: // received demand: unlimited // Subscription: 0x7f81284734c0 // in output handler, received 0 // in output handler, received 1 // in output handler, received 2 // in completion handler ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)