# init(_:traits:arguments:body:) Creates a group of previews of an NSViewController. ``` @MainActor init(_ name: String? = nil, traits: PreviewTrait..., arguments: [T], @PreviewBodyBuilder body: @escaping @MainActor (T) -> NSViewController) ``` ## Parameters `name` An optional display name for the preview. `traits` An optional list of traits to customize the preview. `arguments` An array of arguments to pass into `body`. `body` A closure that maps an argument to an NSViewController to preview. ## Discussion A preview macro expands into a declaration that calls this initializer. Don’t use this initializer directly. --- 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)