Fix doctor false positives and stabilize default RSC starter

react_on_rails/lib/generators/react_on_rails/templates/rsc/base/app/javascript/src/HelloServer/components/HelloServer.jsx

@@ -12,7 +12,6 @@
 // https://www.shakacode.com/react-on-rails-pro/docs/react-server-components/
 
 import React from 'react';
-import LikeButton from './LikeButton';
 
 // Simulate an async data fetch (replace with a real API call or DB query)
 async function fetchGreeting(name) {
@@ -39,7 +38,7 @@ async function fetchGreeting(name) {
     facts: [
       'This component rendered entirely on the server — zero JS was sent to the browser for it.',
       'The date formatting above used server-side Intl APIs — no date library shipped to the client.',
-      'The "Like" button below IS a client component — only its JS is sent to the browser.',
+      'This starter keeps the example server-only so the default scaffold runs cleanly.',
     ],
   };
 }
@@ -70,9 +69,6 @@ const HelloServer = async ({ name = 'World' }) => {
           ))}
         </ul>
       </div>
-
-      {/* LikeButton is a client component — it ships JS for interactivity */}
-      <LikeButton />
     </div>
   );
 };

react_on_rails/lib/generators/react_on_rails/templates/rsc/base/app/javascript/src/HelloServer/components/HelloServer.tsx

@@ -12,7 +12,6 @@
 // https://www.shakacode.com/react-on-rails-pro/docs/react-server-components/
 
 import React from 'react';
-import LikeButton from './LikeButton';
 
 interface HelloServerProps {
   name?: string;
@@ -49,7 +48,7 @@ async function fetchGreeting(name: string): Promise<GreetingData> {
     facts: [
       'This component rendered entirely on the server — zero JS was sent to the browser for it.',
       'The date formatting above used server-side Intl APIs — no date library shipped to the client.',
-      'The "Like" button below IS a client component — only its JS is sent to the browser.',
+      'This starter keeps the example server-only so the default scaffold runs cleanly.',
     ],
   };
 }
@@ -80,9 +79,6 @@ const HelloServer = async ({ name = 'World' }: HelloServerProps) => {
           ))}
         </ul>
       </div>
-
-      {/* LikeButton is a client component — it ships JS for interactivity */}
-      <LikeButton />
     </div>
   );
 };

react_on_rails/lib/generators/react_on_rails/templates/rsc/base/app/views/hello_server/index.html.erb

@@ -13,7 +13,7 @@
   - prerender: true enables server-side rendering with streaming
   - Props are passed from the controller (@hello_server_props)
   - The component streams as it resolves (async data fetching happens server-side)
-  - Only the interactive LikeButton client component ships JS to the browser
+  - The starter example is server-only to keep the initial scaffold deterministic
   - Open DevTools Network tab to verify — no HelloServer.js in the client bundle
 %>
 <%= stream_react_component('HelloServer', props: @hello_server_props, prerender: true) %>

react_on_rails/lib/react_on_rails/system_checker.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 require "open3"
+require "erb"
+require "yaml"
 
 module ReactOnRails
   # SystemChecker provides validation methods for React on Rails setup
@@ -186,17 +188,17 @@ def check_react_on_rails_npm_package
       return unless File.exist?(package_json_path)
 
       package_json = JSON.parse(File.read(package_json_path))
-      npm_version = package_json.dig("dependencies", "react-on-rails") ||
-                    package_json.dig("devDependencies", "react-on-rails")
+      package_name, npm_version = react_on_rails_npm_package_details(package_json)
 
       if npm_version
-        add_success("✅ react-on-rails NPM package #{npm_version} is declared")
+        add_success("✅ #{package_name} NPM package #{npm_version} is declared")
       else
         add_warning(<<~MSG.strip)
-          ⚠️  react-on-rails NPM package not found in package.json.
+          ⚠️  Neither react-on-rails nor react-on-rails-pro NPM package was found in package.json.
 
-          Install it with:
-          npm install react-on-rails
+          Install one with:
+          npm install react-on-rails      # Open source gem
+          npm install react-on-rails-pro  # Pro gem
         MSG
       end
     rescue JSON::ParserError
@@ -208,8 +210,7 @@ def check_package_version_sync
 
       begin
         package_json = JSON.parse(File.read("package.json"))
-        npm_version = package_json.dig("dependencies", "react-on-rails") ||
-                      package_json.dig("devDependencies", "react-on-rails")
+        package_name, npm_version = react_on_rails_npm_package_details(package_json)
 
         return unless npm_version && defined?(ReactOnRails::VERSION)
 
@@ -221,7 +222,7 @@ def check_package_version_sync
         gem_version = ReactOnRails::VERSION
 
         if normalized_npm_version == gem_version
-          add_success("✅ React on Rails gem and NPM package versions match (#{gem_version})")
+          add_success("✅ React on Rails gem and #{package_name} NPM package versions match (#{gem_version})")
           check_version_patterns(npm_version, gem_version)
         else
           # Check for major version differences
@@ -232,7 +233,7 @@ def check_package_version_sync
             add_error(<<~MSG.strip)
               🚫 Major version mismatch detected:
               • Gem version: #{gem_version} (major: #{gem_major})
-              • NPM version: #{npm_version} (major: #{npm_major})
+              • #{package_name} version: #{npm_version} (major: #{npm_major})
 
               Major version differences can cause serious compatibility issues.
               Update both packages to use the same major version immediately.
@@ -241,7 +242,7 @@ def check_package_version_sync
             add_warning(<<~MSG.strip)
               ⚠️  Version mismatch detected:
               • Gem version: #{gem_version}
-              • NPM version: #{npm_version}
+              • #{package_name} version: #{npm_version}
 
               Consider updating to exact, fixed matching versions of gem and npm package for best compatibility.
             MSG
@@ -449,11 +450,55 @@ def normalize_config_content(content)
     end
 
     def required_react_dependencies
-      {
+      deps = {
         "react" => "React library",
-        "react-dom" => "React DOM library",
-        "@babel/preset-react" => "Babel React preset"
+        "react-dom" => "React DOM library"
       }
+
+      deps["@babel/preset-react"] = "Babel React preset" if using_babel_transpiler?
+      deps
+    end
+
+    def react_on_rails_npm_package_details(package_json)
+      all_deps = package_json["dependencies"]&.merge(package_json["devDependencies"] || {}) || {}
+      return ["react-on-rails-pro", all_deps["react-on-rails-pro"]] if all_deps["react-on-rails-pro"]
+      return ["react-on-rails", all_deps["react-on-rails"]] if all_deps["react-on-rails"]
+
+      [nil, nil]
+    end
+
+    def using_babel_transpiler?
+      transpiler = detected_javascript_transpiler
+      return true if transpiler.nil?
+
+      transpiler == "babel"
+    end
+
+    def detected_javascript_transpiler
+      config = parsed_shakapacker_config
+      return nil unless config
+
+      rails_env = ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "development"
+      env_config = config[rails_env] || {}
+      default_config = config["default"] || {}
+      transpiler = env_config["javascript_transpiler"] || default_config["javascript_transpiler"]
+      normalize_transpiler_value(transpiler)
+    end
+
+    def parsed_shakapacker_config
+      shakapacker_config_path = "config/shakapacker.yml"
+      return nil unless File.exist?(shakapacker_config_path)
+
+      raw_content = File.read(shakapacker_config_path)
+      rendered_content = ERB.new(raw_content).result
+      YAML.safe_load(rendered_content, aliases: true) || {}
+    rescue StandardError
+      nil
+    end
+
+    def normalize_transpiler_value(transpiler)
+      normalized = transpiler.to_s.strip.downcase
+      normalized.empty? ? nil : normalized
     end
 
     def additional_build_dependencies

react_on_rails/spec/lib/react_on_rails/system_checker_spec.rb

@@ -304,7 +304,25 @@
       it "adds a warning message" do
         checker.check_react_on_rails_npm_package
         expect(checker.warnings?).to be true
-        expect(checker.messages.last[:content]).to include("react-on-rails NPM package not found")
+        expect(checker.messages.last[:content]).to include("Neither react-on-rails nor react-on-rails-pro")
+      end
+    end
+
+    context "when package.json exists with react-on-rails-pro" do
+      let(:package_json_content) do
+        { "dependencies" => { "react-on-rails-pro" => "^16.0.0" } }.to_json
+      end
+
+      before do
+        allow(File).to receive(:exist?).with("package.json").and_return(true)
+        allow(File).to receive(:read).with("package.json").and_return(package_json_content)
+      end
+
+      it "adds a success message for pro package" do
+        checker.check_react_on_rails_npm_package
+        expect(checker.messages.any? do |msg|
+          msg[:type] == :success && msg[:content].include?("react-on-rails-pro NPM package")
+        end).to be true
       end
     end
 
@@ -356,6 +374,24 @@
       end
     end
 
+    context "when package.json exists with matching versions for react-on-rails-pro" do
+      let(:package_json_content) do
+        { "dependencies" => { "react-on-rails-pro" => "16.2.0-beta.10" } }.to_json
+      end
+
+      before do
+        allow(File).to receive(:exist?).with("package.json").and_return(true)
+        allow(File).to receive(:read).with("package.json").and_return(package_json_content)
+      end
+
+      it "adds a success message" do
+        checker.send(:check_package_version_sync)
+        expect(checker.messages.any? do |msg|
+          msg[:type] == :success && msg[:content].include?("versions match")
+        end).to be true
+      end
+    end
+
     context "when package.json has beta version with caret prefix" do
       let(:package_json_content) do
         { "dependencies" => { "react-on-rails" => "^16.2.0-beta.10" } }.to_json
@@ -480,6 +516,65 @@
     end
   end
 
+  describe "#check_react_dependencies" do
+    let(:base_package_json) do
+      {
+        "dependencies" => {
+          "react" => "^19.0.0",
+          "react-dom" => "^19.0.0"
+        }
+      }
+    end
+
+    before do
+      allow(File).to receive(:exist?).and_call_original
+      allow(File).to receive(:exist?).with("package.json").and_return(true)
+      allow(File).to receive(:read).with("package.json").and_return(base_package_json.to_json)
+    end
+
+    context "when shakapacker javascript_transpiler is swc" do
+      let(:shakapacker_content) do
+        <<~YAML
+          default:
+            javascript_transpiler: swc
+        YAML
+      end
+
+      before do
+        allow(File).to receive(:exist?).with("config/shakapacker.yml").and_return(true)
+        allow(File).to receive(:read).with("config/shakapacker.yml").and_return(shakapacker_content)
+      end
+
+      it "does not warn about missing @babel/preset-react" do
+        checker.check_react_dependencies
+        expect(checker.messages.none? do |msg|
+          msg[:type] == :warning && msg[:content].include?("@babel/preset-react")
+        end).to be true
+      end
+    end
+
+    context "when shakapacker javascript_transpiler is babel" do
+      let(:shakapacker_content) do
+        <<~YAML
+          default:
+            javascript_transpiler: babel
+        YAML
+      end
+
+      before do
+        allow(File).to receive(:exist?).with("config/shakapacker.yml").and_return(true)
+        allow(File).to receive(:read).with("config/shakapacker.yml").and_return(shakapacker_content)
+      end
+
+      it "warns when @babel/preset-react is missing" do
+        checker.check_react_dependencies
+        expect(checker.messages.any? do |msg|
+          msg[:type] == :warning && msg[:content].include?("@babel/preset-react")
+        end).to be true
+      end
+    end
+  end
+
   describe "private methods" do
     describe "#cli_exists?" do
       it "returns true when command exists" do

react_on_rails/spec/react_on_rails/generators/install_generator_spec.rb

@@ -782,6 +782,13 @@
       end
     end
 
+    it "keeps default HelloServer component server-only" do
+      assert_file "app/javascript/src/HelloServer/components/HelloServer.jsx" do |content|
+        expect(content).not_to include("import LikeButton")
+        expect(content).not_to include("<LikeButton />")
+      end
+    end
+
     it "adds HelloServer route" do
       assert_file "config/routes.rb" do |content|
         expect(content).to include("hello_server")
@@ -863,6 +870,13 @@
       assert_file "app/javascript/src/HelloServer/components/LikeButton.tsx"
     end
 
+    it "keeps TypeScript HelloServer component server-only by default" do
+      assert_file "app/javascript/src/HelloServer/components/HelloServer.tsx" do |content|
+        expect(content).not_to include("import LikeButton")
+        expect(content).not_to include("<LikeButton />")
+      end
+    end
+
     it "creates tsconfig.json file" do
       assert_file "tsconfig.json" do |content|
         config = JSON.parse(content)