Load associations for all records with the same object_id

README.md

@@ -40,8 +40,8 @@ Call `preload` when defining your field:
         # Post.includes(:comments, :authors)
         preload [:comments, :authors]
 
-        # Post.includes(:comments, authors: [:posts, :followers])
-        preload [:comments, { authors: [:posts, :followers] }]
+        # Post.includes(:comments, authors: [:followers, :posts])
+        preload [:comments, { authors: [:followers, :posts] }]
 
         resolve ->(obj, args, ctx) { obj.comments }
       end

lib/graphql/preload/instrument.rb

@@ -33,17 +33,17 @@ def instrument(_type, field)
               promises << preload(record, sub_association)
             end
           when Hash
-            association.each do |sub_association, property|
+            association.each do |sub_association, nested_association|
               promises << preload_single_association(record, sub_association).then do
                 associated_records = record.public_send(sub_association)
 
                 case associated_records
                 when ActiveRecord::Base
-                  preload(associated_records, property)
+                  preload(associated_records, nested_association)
                 else
                   Promise.all(
                     Array.wrap(associated_records).map do |associated_record|
-                      preload(associated_record, property)
+                      preload(associated_record, nested_association)
                     end
                   )
                 end
@@ -56,7 +56,6 @@ def instrument(_type, field)
       end
 
       private def preload_single_association(record, association)
-        return Promise.resolve(record) if record.association(association).loaded?
         GraphQL::Preload::Loader.for(record.class, association).load(record)
       end
     end

lib/graphql/preload/loader.rb

@@ -4,6 +4,10 @@ module Preload
     class Loader < GraphQL::Batch::Loader
       attr_reader :association, :model
 
+      def cache_key(record)
+        record.object_id
+      end
+
       def initialize(model, association)
         @association = association
         @model = model
@@ -13,38 +17,41 @@ def initialize(model, association)
 
       def load(record)
         unless record.is_a?(model)
-          raise TypeError, "loader for #{model.name} can't load associations for #{record.class.name} objects"
+          raise TypeError, "Loader for #{model} can't load associations for #{record.class} objects"
         end
 
-        if record.association(association).loaded?
-          Promise.resolve(record)
-        else
-          super
-        end
+        return Promise.resolve(record) if association_loaded?(record)
+        super
       end
 
       def perform(records)
+        preload_association(records)
+        records.each { |record| fulfill(record, record) }
+      end
+
+      private def association_loaded?(record)
+        record.association(association).loaded?
+      end
+
+      private def preload_association(records)
         if ActiveRecord::VERSION::MAJOR > 3
           ActiveRecord::Associations::Preloader.new.preload(records, association)
         else
           ActiveRecord::Associations::Preloader.new(records, association).run
         end
-
-        records.each { |record| fulfill(record, record) }
       end
 
       private def validate_association
         unless association.is_a?(Symbol)
-          raise ArgumentError, 'association must be a Symbol object'
+          raise ArgumentError, 'Association must be a Symbol object'
         end
 
         unless model < ActiveRecord::Base
-          raise ArgumentError, 'model must be an ActiveRecord::Base descendant'
+          raise ArgumentError, 'Model must be an ActiveRecord::Base descendant'
         end
 
         return if model.reflect_on_association(association)
-
-        raise TypeError, "association :#{association} does not exist on #{model.name}"
+        raise TypeError, "Association :#{association} does not exist on #{model}"
       end
     end
   end

lib/graphql/preload/version.rb

@@ -1,5 +1,5 @@
 module GraphQL
   module Preload
-    VERSION = '1.0.2'.freeze
+    VERSION = '1.0.3'.freeze
   end
 end