Add InertiaRails.defer prop

Co-authored-by: Svyatoslav Kryukov <[email protected]>

Author: 2 people

lib/inertia_rails/defer_prop.rb

@@ -0,0 +1,12 @@
+module InertiaRails
+  class DeferProp < IgnoreOnFirstLoadProp
+    DEFAULT_GROUP = "default".freeze
+
+    attr_reader :group
+
+    def initialize(group: nil, &block)
+      @group = group || DEFAULT_GROUP
+      @block = block
+    end
+  end
+end

lib/inertia_rails/ignore_on_first_load_prop.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+module InertiaRails
+  class IgnoreOnFirstLoadProp < BaseProp
+  end
+end

lib/inertia_rails/inertia_rails.rb

@@ -1,6 +1,8 @@
 require 'inertia_rails/base_prop'
+require 'inertia_rails/ignore_on_first_load_prop'
 require 'inertia_rails/always_prop'
 require 'inertia_rails/lazy_prop'
+require 'inertia_rails/defer_prop'
 require 'inertia_rails/configuration'
 
 module InertiaRails
@@ -22,5 +24,9 @@ def lazy(value = nil, &block)
     def always(&block)
       AlwaysProp.new(&block)
     end
+
+    def defer(group: nil, &block)
+      DeferProp.new(group:, &block)
+    end
   end
 end

lib/inertia_rails/lazy_prop.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module InertiaRails
-  class LazyProp < BaseProp
+  class LazyProp < IgnoreOnFirstLoadProp
     def initialize(value = nil, &block)
       raise ArgumentError, 'You must provide either a value or a block, not both' if value && block
 

lib/inertia_rails/renderer.rb

@@ -96,12 +96,17 @@ def computed_props
     end
 
     def page
-      {
+      default_page = {
         component: component,
         props: computed_props,
         url: @request.original_fullpath,
         version: configuration.version,
       }
+
+      deferred_props = deferred_props_keys
+      default_page[:deferredProps] = deferred_props if deferred_props.present?
+
+      default_page
     end
 
     def deep_transform_props(props, parent_path = [], &block)
@@ -120,6 +125,15 @@ def deep_transform_props(props, parent_path = [], &block)
       end
     end
 
+    def deferred_props_keys
+      return if rendering_partial_component?
+
+      @props.select { |_, prop| prop.is_a?(DeferProp) }
+            .map { |key, prop| { key: key, group: prop.group } }
+            .group_by { |prop| prop[:group] }
+            .transform_values { |props| props.map { |prop| prop[:key].to_s } }
+    end
+
     def partial_keys
       (@request.headers['X-Inertia-Partial-Data'] || '').split(',').compact
     end
@@ -148,7 +162,7 @@ def keep_prop?(prop, path)
       end
 
       # Precedence: Evaluate LazyProp only after partial keys have been checked
-      return false if prop.is_a?(LazyProp) && !rendering_partial_component?
+      return false if prop.is_a?(IgnoreOnFirstLoadProp) && !rendering_partial_component?
 
       true
     end

spec/dummy/app/controllers/inertia_render_test_controller.rb

@@ -93,4 +93,15 @@ def always_props
       another_lazy: InertiaRails.lazy(->{ 'another lazy prop' })
     }
   end
+
+  def deferred_props
+    render inertia: 'TestComponent', props: {
+      name: 'Brian',
+      sport: InertiaRails.defer(group: 'other') { 'basketball' },
+      level: InertiaRails.defer do
+        'worse than he believes'
+      end,
+      grit: InertiaRails.defer { 'intense' }
+    }
+  end
 end

spec/dummy/config/routes.rb

@@ -33,6 +33,7 @@
   get 'lazy_props' => 'inertia_render_test#lazy_props'
   get 'always_props' => 'inertia_render_test#always_props'
   get 'except_props' => 'inertia_render_test#except_props'
+  get 'deferred_props' => 'inertia_render_test#deferred_props'
   get 'non_inertiafied' => 'inertia_test#non_inertiafied'
   get 'deeply_nested_props' => 'inertia_render_test#deeply_nested_props'
 

spec/inertia/rendering_spec.rb

@@ -393,6 +393,48 @@
       end
     end
   end
+
+  context 'deferred prop rendering' do
+    context 'on first load' do
+      let (:page) {
+        InertiaRails::Renderer.new('TestComponent', controller, request, response, '', props: { name: 'Brian', sport: 'basketball', level: 'worse than he believes', grit: 'intense' }).send(:page)
+      }
+      let(:headers) { { 'X-Inertia' => true } }
+      before { get deferred_props_path, headers: headers }
+
+      it "does not include defer props inside props in first load" do
+        expect(JSON.parse(response.body)["props"]).to eq({ "name" => 'Brian' })
+      end
+
+      it "returns deferredProps" do
+        expect(JSON.parse(response.body)["deferredProps"]).to eq(
+          "default" => ["level", "grit"],
+          "other" => ["sport"]
+        )
+      end
+    end
+
+    context 'with a partial reload' do
+      let (:page) {
+        InertiaRails::Renderer.new('TestComponent', controller, request, response, '', props: { sport: 'basketball', level: 'worse than he believes', grit: 'intense' }).send(:page)
+      }
+      let(:headers) { {
+        'X-Inertia' => true,
+        'X-Inertia-Partial-Data' => 'level,grit', # Simulate default group
+        'X-Inertia-Partial-Component' => 'TestComponent',
+      } }
+
+      before { get deferred_props_path, headers: headers }
+
+      it { is_expected.to eq page.to_json }
+      it { is_expected.to include('intense') }
+      it { is_expected.to include('worse') }
+      it { is_expected.not_to include('basketball') }
+      it "does not deferredProps key in json" do
+        expect(JSON.parse(response.body)["deferredProps"]).to eq(nil)
+      end
+    end
+  end
 end
 
 def inertia_div(page)