Add InertiaRails.merge prop

Author: skryukov

lib/inertia_rails/defer_prop.rb

@@ -1,12 +1,19 @@
+# frozen_string_literal: true
+
 module InertiaRails
   class DeferProp < IgnoreOnFirstLoadProp
-    DEFAULT_GROUP = "default".freeze
+    DEFAULT_GROUP = "default"
 
     attr_reader :group
 
-    def initialize(group: nil, &block)
+    def initialize(group: nil, merge: nil, &block)
       @group = group || DEFAULT_GROUP
+      @merge = merge
       @block = block
     end
+
+    def merge?
+      @merge
+    end
   end
 end

lib/inertia_rails/inertia_rails.rb

@@ -3,6 +3,7 @@
 require 'inertia_rails/always_prop'
 require 'inertia_rails/lazy_prop'
 require 'inertia_rails/defer_prop'
+require 'inertia_rails/merge_prop'
 require 'inertia_rails/configuration'
 
 module InertiaRails
@@ -25,8 +26,12 @@ def always(&block)
       AlwaysProp.new(&block)
     end
 
-    def defer(group: nil, &block)
-      DeferProp.new(group:, &block)
+    def merge(&block)
+      MergeProp.new(&block)
+    end
+
+    def defer(group: nil, merge: nil, &block)
+      DeferProp.new(group: group, merge: merge, &block)
     end
   end
 end

lib/inertia_rails/merge_prop.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module InertiaRails
+  class MergeProp < BaseProp
+    def initialize(*)
+      super
+      @merge = true
+    end
+
+    def merge?
+      @merge
+    end
+  end
+end

lib/inertia_rails/renderer.rb

@@ -2,7 +2,7 @@
 
 require 'net/http'
 require 'json'
-require_relative "inertia_rails"
+require_relative 'inertia_rails'
 
 module InertiaRails
   class Renderer
@@ -112,6 +112,9 @@ def page
       deferred_props = deferred_props_keys
       default_page[:deferredProps] = deferred_props if deferred_props.present?
 
+      merge_props = merge_props_keys
+      default_page[:mergeProps] = merge_props if merge_props.present?
+
       default_page
     end
 
@@ -134,14 +137,25 @@ def deep_transform_props(props, parent_path = [], &block)
     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 } }
+      @props.each_with_object({}) do |(key, prop), result|
+        (result[prop.group] ||= []) << key if prop.is_a?(DeferProp)
+      end
+    end
+
+    def merge_props_keys
+      @props.each_with_object([]) do |(key, prop), result|
+        if prop.try(:merge?) && reset_keys.exclude?(key)
+          result << key
+        end
+      end
     end
 
     def partial_keys
-      (@request.headers['X-Inertia-Partial-Data'] || '').split(',').compact
+      @partial_keys ||= (@request.headers['X-Inertia-Partial-Data'] || '').split(',').compact
+    end
+
+    def reset_keys
+      (@request.headers['X-Inertia-Reset'] || '').split(',').compact.map(&:to_sym)
     end
 
     def partial_except_keys

spec/dummy/app/controllers/inertia_render_test_controller.rb

@@ -94,6 +94,15 @@ def always_props
     }
   end
 
+  def merge_props
+    render inertia: 'TestComponent', props: {
+      merge: InertiaRails.merge { 'merge prop' },
+      regular: 'regular prop',
+      deferred_merge: InertiaRails.defer(merge: true) { 'deferred and merge prop'},
+      deferred: InertiaRails.defer { 'deferred' },
+    }
+  end
+
   def deferred_props
     render inertia: 'TestComponent', props: {
       name: 'Brian',

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 'merge_props' => 'inertia_render_test#merge_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

@@ -394,6 +394,47 @@
     end
   end
 
+  context 'merged prop rendering' do
+    let(:headers) { { 'X-Inertia' => true } }
+
+    before { get merge_props_path, headers: headers }
+
+    it 'returns non-optional props and meta on first load' do
+      expect(response.parsed_body['props']).to eq('merge' => 'merge prop', 'regular' => 'regular prop')
+      expect(response.parsed_body['mergeProps']).to match_array(%w[merge deferred_merge])
+      expect(response.parsed_body['deferredProps']).to eq('default' => %w[deferred_merge deferred])
+    end
+
+    context 'with a partial reload' do
+      let(:headers) {{
+        'X-Inertia' => true,
+        'X-Inertia-Partial-Data' => 'deferred_merge',
+        'X-Inertia-Partial-Component' => 'TestComponent',
+      }}
+
+      it 'returns listed and merge props' do
+        expect(response.parsed_body['props']).to eq({'deferred_merge' => 'deferred and merge prop'})
+        expect(response.parsed_body['mergeProps']).to match_array(%w[merge deferred_merge])
+        expect(response.parsed_body['deferredProps']).to be_nil
+      end
+    end
+
+    context 'with a reset header' do
+      let(:headers) {{
+        'X-Inertia' => true,
+        'X-Inertia-Partial-Data' => 'deferred_merge',
+        'X-Inertia-Partial-Component' => 'TestComponent',
+        'X-Inertia-Reset' => 'deferred_merge'
+      }}
+
+      it 'returns listed and merge props' do
+        expect(response.parsed_body['props']).to eq({'deferred_merge' => 'deferred and merge prop'})
+        expect(response.parsed_body['mergeProps']).to match_array(%w[merge])
+        expect(response.parsed_body['deferredProps']).to be_nil
+      end
+    end
+  end
+
   context 'deferred prop rendering' do
     context 'on first load' do
       let (:page) {