Add OpenGraph helper module.

examples/docs/src/OpenGraph.elm

@@ -0,0 +1,46 @@
+module OpenGraph exposing (website)
+
+{-| <https://ogp.me/#>
+-}
+
+import Pages.Head as Head
+
+
+{-| <https://ogp.me/#type_website>
+-}
+website :
+    { url : String
+    , name : String
+    , imageUrl : Maybe String
+    }
+    -> List Head.Tag
+website details =
+    Website details
+        |> tags
+
+
+type Content
+    = Website
+        { url : String
+        , name : String
+        , imageUrl : Maybe String
+        }
+
+
+tags content =
+    case content of
+        Website details ->
+            [ ( "og:type", Just "website" )
+            , ( "og:url", Just details.url )
+            , ( "og:locale", Just "en" )
+            , ( "og:site_name", Just details.name )
+            , ( "og:image", details.imageUrl )
+
+            -- , ( "og:image:width", Just "512" )
+            -- , ( "og:image:height", Just "512" )
+            ]
+                |> List.filterMap
+                    (\( name, maybeContent ) ->
+                        maybeContent
+                            |> Maybe.map (\metaContent -> Head.metaName name metaContent)
+                    )