---
title: "on(completionHandler:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrbaseclusteronoff/on(completionhandler:)"
---

# on(completionHandler:)

## Declaration

```swift
func on(completionHandler: @escaping @Sendable ((any Error)?) -> Void)
```

```swift
func on() async throws
```