---
title: "onAppear(perform:)"
framework: swiftui
role: symbol
role_heading: Instance Method
path: "swiftui/compositorcontent/onappear(perform:)"
---

# onAppear(perform:)

Adds an action to perform before this content appears.

## Declaration

```swift
nonisolated func onAppear(perform action: (() -> Void)? = nil) -> some CompositorContent

```

## Parameters

- `action`: The action to perform. If action is nil, the call has no effect.

## Return Value

Return Value A CompositorContent that triggers action before it appears.

## Discussion

Discussion The exact moment that SwiftUI calls this method depends on the specific content type that you apply it to, but the action closure completes before the first rendered frame appears.