diff --git a/lib/shared/messages/reaction-message-spec.js b/lib/shared/messages/reaction-message-spec.js
--- a/lib/shared/messages/reaction-message-spec.js
+++ b/lib/shared/messages/reaction-message-spec.js
@@ -108,6 +108,14 @@
     };
   },
 
+  rawMessageInfoFromMessageData(
+    messageData: ReactionMessageData,
+    id: ?string,
+  ): RawReactionMessageInfo {
+    invariant(id, 'RawReactionMessageInfo needs id');
+    return { ...messageData, id };
+  },
+
   shimUnsupportedMessageInfo(
     rawMessageInfo: RawReactionMessageInfo,
     platformDetails: ?PlatformDetails,