---
title: "handleEvents(receiveSubscription:receiveOutput:receiveCompletion:receiveCancel:receiveRequest:)"
framework: combine
role: symbol
role_heading: Instance Method
path: "combine/publisher/handleevents(receivesubscription:receiveoutput:receivecompletion:receivecancel:receiverequest:)"
---

# handleEvents(receiveSubscription:receiveOutput:receiveCompletion:receiveCancel:receiveRequest:)

Performs the specified closures when publisher events occur.

## Declaration

```swift
func handleEvents(receiveSubscription: ((any Subscription) -> Void)? = nil, receiveOutput: ((Self.Output) -> Void)? = nil, receiveCompletion: ((Subscribers.Completion<Self.Failure>) -> Void)? = nil, receiveCancel: (() -> Void)? = nil, receiveRequest: ((Subscribers.Demand) -> Void)? = nil) -> Publishers.HandleEvents<Self>
```

## 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

Return Value A publisher that performs the specified closures when publisher events occur.

## Discussion

Discussion Use 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

## See Also

### Debugging

- [breakpoint(receiveSubscription:receiveOutput:receiveCompletion:)](combine/publisher/breakpoint(receivesubscription:receiveoutput:receivecompletion:).md)
- [breakpointOnError()](combine/publisher/breakpointonerror().md)
- [print(_:to:)](combine/publisher/print(_:to:).md)