feat(ServerRendering) reload when new files are added; support configurable reloader globs

Author: rmosolgo

README.md

@@ -189,6 +189,9 @@ MyApp::Application.configure do
     files: ["server_rendering.js"],       # files to load for prerendering
     replay_console: true,                 # if true, console.* will be replayed client-side
   }
+  # Changing files matching these dirs/exts will cause the server renderer to reload:
+  config.react.server_renderer_extensions = ["jsx"]
+  config.react.server_renderer_directories = ["/app/assets/javascripts"]
 end
 ```
 

lib/react/rails/railtie.rb

@@ -17,12 +17,22 @@ class Railtie < ::Rails::Railtie
       config.react.server_renderer_timeout    = 20  # seconds
       config.react.server_renderer            = nil # defaults to SprocketsRenderer
       config.react.server_renderer_options    = {}  # SprocketsRenderer provides defaults
+      # Changing files with these extensions in these directories will cause the server renderer to reload:
+      config.react.server_renderer_directories = ["/app/assets/javascripts/"]
+      config.react.server_renderer_extensions = ["jsx"]
       # View helper implementation:
       config.react.view_helper_implementation = nil # Defaults to ComponentMount
 
       # Watch .jsx files for changes in dev, so we can reload the JS VMs with the new JS code.
       initializer "react_rails.add_watchable_files", group: :all do |app|
-        app.config.watchable_files.concat Dir["#{app.root}/app/assets/javascripts/**/*.jsx*"]
+        reload_paths = config.react.server_renderer_directories.reduce({}) do |memo, dir|
+          app_dir = File.join(app.root, dir)
+          memo[app_dir] = config.react.server_renderer_extensions
+          memo
+        end
+        app.reloaders << ActiveSupport::FileUpdateChecker.new([], reload_paths) do
+          React::ServerRendering.reset_pool
+        end
       end
 
       # Include the react-rails view helper lazily

test/server_rendered_html_test.rb

@@ -37,6 +37,27 @@ def wait_to_ensure_asset_pipeline_detects_changes
       end
     end
 
+    test 'it reloads when new jsx files are added' do
+      begin
+        get '/server/1'
+        refute_match(/Overwritten List/, response.body)
+
+        # Make it alphabetically last so it will override the preceeding one:
+        new_file_path = File.expand_path('../dummy/app/assets/javascripts/components/ZZ_NewComponent.js.jsx', __FILE__)
+        File.write new_file_path, <<-JS
+        var TodoList = function() { return <span>"Overwritten List"</span> }
+        JS
+
+        wait_to_ensure_asset_pipeline_detects_changes
+
+        get '/server/1'
+        assert_match(/Overwritten List/, response.body)
+      ensure
+        FileUtils.rm_rf(new_file_path)
+        wait_to_ensure_asset_pipeline_detects_changes
+      end
+    end
+
     test 'react server rendering shows console output as html comment' do
       # Make sure console messages are replayed when requested
       get '/server/console_example'