Allow decorating objects after pagination

lib/jsonapi/pagination.rb

@@ -13,14 +13,13 @@ module Pagination
     def jsonapi_paginate(resources)
       offset, limit, _ = jsonapi_pagination_params
 
+      # Cache the original resources size to be used for pagination meta
+      @_jsonapi_original_size = resources.size
+
       if resources.respond_to?(:offset)
         resources = resources.offset(offset).limit(limit)
       else
-        original_size = resources.size
         resources = resources[(offset)..(offset + limit - 1)] || []
-
-        # Cache the original resources size to be used for pagination meta
-        resources.instance_variable_set(:@original_size, original_size)
       end
 
       block_given? ? yield(resources) : resources
@@ -64,13 +63,7 @@ def jsonapi_pagination_meta(resources)
 
       numbers = { current: page }
 
-      if resources.respond_to?(:unscope)
-        total = resources.unscope(:limit, :offset, :order).size
-      else
-        # Try to fetch the cached size first
-        total = resources.instance_variable_get(:@original_size)
-        total ||= resources.size
-      end
+      total = @_jsonapi_original_size
 
       last_page = [1, (total.to_f / limit).ceil].max
 

spec/dummy.rb

@@ -119,6 +119,7 @@ def index
       result = result.to_a if params[:as_list]
 
       jsonapi_paginate(result) do |paginated|
+        paginated = paginated.to_a if params[:decorate_after_pagination]
         render jsonapi: paginated
       end
     end

spec/pagination_spec.rb

@@ -53,11 +53,13 @@
 
         context 'on page 2 out of 3' do
           let(:as_list) { }
+          let(:decorate_after_pagination) { }
           let(:params) do
             {
               page: { number: 2, size: 1 },
               sort: '-created_at',
-              as_list: as_list
+              as_list: as_list,
+              decorate_after_pagination: decorate_after_pagination
             }.compact_blank
           end
 
@@ -80,6 +82,25 @@
             end
           end
 
+          context 'when decorating objects after pagination' do
+            let(:decorate_after_pagination) { true }
+
+            it do
+              expect(response).to have_http_status(:ok)
+              expect(response_json['data'].size).to eq(1)
+              expect(response_json['data'][0]).to have_id(second_user.id.to_s)
+
+              expect(response_json['meta']['pagination']).to eq(
+                'current' => 2,
+                'first' => 1,
+                'prev' => 1,
+                'next' => 3,
+                'last' => 3,
+                'records' => 3
+              )
+            end
+          end
+
           it do
             expect(response).to have_http_status(:ok)
             expect(response_json['data'].size).to eq(1)