# Preview(_:as:widget:timeline:) Preview a timeline-style widget. ``` @freestanding(declaration) macro Preview(_ name: String? = nil, as family: WidgetFamily, widget: @escaping () -> Widget, @PreviewTimelineBuilder timeline: @escaping @MainActor () async -> [any TimelineEntry]) where Widget : Widget ``` ## Parameters `name` An optional display name for the preview that appears in the Xcode preview canvas. `family` The widget family to display. `widget` A closure producing the widget to be previewed. `timeline` A closure building the timeline of entries to be previewed. ## Overview Provide the preview with sample data and use it to step through the timeline while ignoring the dates of the entries, and test out the transitions between them. > Note: The timeline entries must be of the type that the widget expects. --- 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)