---
title: "callAsFunction(contentType:prepareDocument:)"
framework: swiftui
role: symbol
role_heading: Instance Method
path: "swiftui/newdocumentaction/callasfunction(contenttype:preparedocument:)"
---

# callAsFunction(contentType:prepareDocument:)

Presents a new document window with preset contents.

## Declaration

```swift
@MainActor @preconcurrency func callAsFunction(contentType: UTType, prepareDocument: @escaping (ModelContext) -> Void)
```

## Parameters

- `contentType`: The content type of the document.
- `prepareDocument`: The closure that accepts ModelContext associated with the new document. Use this closure to set the document’s initial contents before it is displayed: insert preconfigured models in the provided ModelContext.

## Discussion

Discussion Don’t call this method directly. SwiftUI calls it when you call the newDocument action. For example, a Todo app might have a way to create a sample prepopulated Todo list as a part of onboarding experience: newDocument(contentType: .todoList) { modelContext in     let todoList = TodoList(         title: "🎬 Movie night",         items: [             TodoItem(title: "🍿 Buy popcorn"),             TodoItem(title: "🍨 Make some ice cream",             TodoItem(title: "💡 Hang a string of lights")         ]     )     modelContext.insert(todoList) } For information about how Swift uses the callAsFunction() method to simplify call site syntax, see Methods with Special Names in The Swift Programming Language.

## See Also

### Calling the action

- [callAsFunction(_:)](swiftui/newdocumentaction/callasfunction(_:).md)
- [callAsFunction(contentType:)](swiftui/newdocumentaction/callasfunction(contenttype:).md)