Dataloading links_fields

app/graphql/sources/linked_to_editions_source.rb

@@ -0,0 +1,23 @@
+module Sources
+  class LinkedToEditionsSource < GraphQL::Dataloader::Source
+    def initialize(parent_object:)
+      @object = parent_object
+      @content_store = parent_object.content_store.to_sym
+    end
+
+    def fetch(link_types)
+      all_links = @object.document.link_set_links
+        .includes(target_documents: @content_store) # content_store is :live or :draft (a Document has_one Edition by that name)
+        .where(link_type: link_types)
+        .where(target_documents: { locale: "en" })
+
+      link_types_map = link_types.index_with { [] }
+
+      all_links.each_with_object(link_types_map) { |link, hash|
+        hash[link.link_type].concat(
+          link.target_documents.map { |document| document.send(@content_store) },
+        )
+      }.values
+    end
+  end
+end

app/graphql/types/base_object.rb

@@ -10,15 +10,8 @@ def self.links_field(field_name_and_link_type, graphql_field_type)
       field(field_name_and_link_type.to_sym, graphql_field_type)
 
       define_method(field_name_and_link_type.to_sym) do
-        Edition
-          .live
-          .includes(document: { reverse_links: :link_set })
-          .where(
-            document: { locale: "en" },
-            link_set: { content_id: object.content_id },
-            reverse_links: { link_type: field_name_and_link_type.to_s },
-          )
-          .order(reverse_links: { position: :asc })
+        dataloader.with(Sources::LinkedToEditionsSource, parent_object: object)
+          .load(field_name_and_link_type.to_s)
       end
     end
   end