Extract items from category for search in frontend

src/invidious/search.cr

@@ -231,5 +231,20 @@ def process_search_query(url_params, query, page, user, region)
     count, items = search(search_query, search_params, region).as(Tuple)
   end
 
-  {search_query, count, items, url_params}
+  # Light processing to extract items from categories.
+  # Categories should ideally be supported in the frontend in the future
+  extracted_items = [] of SearchItem | ChannelVideo
+  items.each do |i|
+    if i.is_a? Category
+      i.contents.each do |cate_items|
+        if cate_items.is_a? (SearchVideo | SearchPlaylist | SearchChannel)
+          extracted_items << cate_items
+        end
+      end
+    else
+      extracted_items << i
+    end
+  end 
+
+  {search_query, count, extracted_items, url_params}
 end