Added the alternate locales to the Social Card in the Infrastructure package.

Packages/Infrastructure/Sources/Public/Types/SocialCard.swift

@@ -7,6 +7,9 @@ public struct SocialCard: Sendable {
 
     // MARK: Properties
 
+    /// The locales of the card's other language editions, in Open Graph's `language_TERRITORY` form; empty to omit their tags.
+    public let alternateLocales: [String]
+
     /// The card's share image, or `nil` to omit its tags.
     public let image: Image?
 
@@ -43,6 +46,7 @@ public struct SocialCard: Sendable {
     ///   - siteName: the name of the site the card belongs to, or `nil` (the default) to omit its tag.
     ///   - locale: the locale of the card's text, ideally in Open Graph's `language_TERRITORY` form (e.g. `en_US`), or `nil` (the default)
     ///     to omit its tag.
+    ///   - alternateLocales: the locales the card's page is also published in, in the same form; empty (the default) to omit their tags.
     ///   - image: the card's share image, or `nil` (the default) to omit its tags.
     ///   - type: the Open Graph type of the object the card describes. Defaults to `website`.
     ///   - style: the layout a Twitter card scraper gives the card. Defaults to ``Style/summaryLargeImage``.
@@ -52,10 +56,12 @@ public struct SocialCard: Sendable {
         url: String? = nil,
         siteName: String? = nil,
         locale: String? = nil,
+        alternateLocales: [String] = [],
         image: Image? = nil,
         type: String = "website",
         style: Style = .summaryLargeImage
     ) {
+        self.alternateLocales = alternateLocales
         self.image = image
         self.locale = locale
         self.siteName = siteName
@@ -68,8 +74,8 @@ public struct SocialCard: Sendable {
 
     // MARK: Computed
 
-    /// The card's meta tags, in a stable order: the Open Graph type, site name, title, description, URL, and locale, then the image group, and
-    /// the Twitter card style last. A tag whose fact the card does not carry is left out.
+    /// The card's meta tags, in a stable order: the Open Graph type, site name, title, description, URL, locale, and alternate locales, then the
+    /// image group, and the Twitter card style last. A tag whose fact the card does not carry is left out.
     public var tags: [Tag] {
         let tags: [Tag?] = [
             Tag(type, name: .type),
@@ -78,7 +84,7 @@ public struct SocialCard: Sendable {
             summary.map { Tag($0, name: .description) },
             url.map { Tag($0, name: .url) },
             locale.map { Tag($0, name: .locale) },
-        ] + (image?.tags ?? []) + [
+        ] + alternateLocales.map { Tag($0, name: .localeAlternate) } + (image?.tags ?? []) + [
             Tag(style.rawValue, name: .twitter),
         ]
 

Packages/Infrastructure/Sources/Public/Types/SocialCard/SocialCardTag.swift

@@ -60,6 +60,7 @@ extension SocialCard.Tag {
         case imageWidth = "og:image:width"
         /// The `og:locale` tag, carrying the locale of the card's text.
         case locale = "og:locale"
+        case localeAlternate = "og:locale:alternate"
         /// The `og:site_name` tag, carrying the name of the site the card belongs to.
         case siteName = "og:site_name"
         /// The `og:title` tag, carrying the card's title.

Packages/Infrastructure/Tests/Cases/Public/Types/SocialCardTests.swift

@@ -18,6 +18,7 @@ struct SocialCardTests {
             url: "https://site.example/",
             siteName: "A Site",
             locale: "en",
+            alternateLocales: ["nl_NL", "de_DE"],
             image: .init(
                 url: "https://site.example/img/card.png",
                 width: 2400,
@@ -33,6 +34,8 @@ struct SocialCardTests {
             .init("A summary.", name: .description),
             .init("https://site.example/", name: .url),
             .init("en", name: .locale),
+            .init("nl_NL", name: .localeAlternate),
+            .init("de_DE", name: .localeAlternate),
             .init("https://site.example/img/card.png", name: .image),
             .init("2400", name: .imageWidth),
             .init("1260", name: .imageHeight),