A method for specifying multiplatform widget families in Swift.

MultiplatformWidgetFamily.swift

import SwiftUI
import WidgetKit

@available(iOS 16.0, macOS 13.0, *)
public enum MultiplatformWidgetFamily: CaseIterable {
    
    /// A small widget.
    ///
    /// The small system widget can appear on the Home Screen or in the Today View in iOS and iPadOS, or in the Notification Center on macOS.
    case systemSmall
    
    /// A medium-sized widget.
    ///
    /// The medium system widget can appear on the Home Screen or in the Today View in iOS and iPadOS, or in the Notification Center on macOS.
    case systemMedium
    
    /// A large widget.
    ///
    /// The large system widget can appear on the Home Screen or in the Today View in iOS or iPadOS, or in the Notification Center on macOS.
    case systemLarge
    
    /// An extra large widget.
    ///
    /// The extra-large system widget can appear on the Home Screen in iPadOS.
    case systemExtraLarge
    
    /// A circular widget.
    ///
    /// The accessory circular widget can appear as a complication in watchOS, or on the Lock Screen in iOS.
    case accessoryCircular
    
    /// A rectangular widget.
    ///
    /// The accessory rectangular widget can appear as a complication in watchOS or on the Lock Screen in iOS.
    case accessoryRectangular
    
    /// A flat widget that contains a single row of text and an optional image.
    ///
    /// The accessory inline widget can appear as a complication in watchOS, or on the Lock Screen in iOS. On some watch faces, the system renders the complication along a curve.
    case accessoryInline
    
    /// Provides the counterpart `WidgetFamily` value if available for the current platform.
    var widgetFamilyValue: WidgetFamily? {
        switch self {
        case .systemSmall:
            return .systemSmall
        case .systemMedium:
            return .systemMedium
        case .systemLarge:
            return .systemLarge
        case .systemExtraLarge:
            #if os(iOS)
            return .systemExtraLarge
            #elseif os(macOS)
            return nil
            #endif
        case .accessoryCircular:
            #if os(iOS)
            return .accessoryCircular
            #elseif os(macOS)
            return nil
            #endif
        case .accessoryRectangular:
            #if os(iOS)
            return .accessoryRectangular
            #elseif os(macOS)
            return nil
            #endif
        case .accessoryInline:
            #if os(iOS)
            return .accessoryInline
            #elseif os(macOS)
            return nil
            #endif
        }
    }
    
}

@available(iOS 16.0, macOS 13.0, *)
public extension WidgetConfiguration {
    
    /// Sets the sizes that a widget supports for the families that are available for the current platform.
    ///
    /// - Parameters:
    ///   - multiplatformFamilies: The set of sizes the widget supports across all platforms.
    ///
    /// - Returns: A widget configuration that supports the available sizes.
    func multiplatformSupportedFamilies(_ multiplatformFamilies: [MultiplatformWidgetFamily]) -> some WidgetConfiguration {
        let widgetFamilies = multiplatformFamilies.compactMap(\.widgetFamilyValue)
        return supportedFamilies(widgetFamilies)
    }
    
}