Add comprehensive test coverage and type signatures for JsDependencyManager

- Add RBS type signatures for JsDependencyManager module
- Add comprehensive test suite covering all dependency installation scenarios
- Improve error handling with better edge case coverage
- Update tests to verify Rspack and TypeScript dependency flows
- Document breaking changes in CHANGELOG for Babel dependency removal

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

CHANGELOG.md

@@ -57,6 +57,8 @@ Changes since the last non-beta release.
 
 - **Generator Configuration Modernization**: Updated the generator to enable recommended configurations by default for new applications. `config.build_test_command` is now uncommented and set to `"RAILS_ENV=test bin/shakapacker"` by default, enabling automatic asset building during tests for better integration test reliability. `config.auto_load_bundle = true` is now set by default, enabling automatic loading of component bundles. `config.components_subdirectory = "ror_components"` is now set by default, organizing React components in a dedicated subdirectory. **Note:** These changes only affect newly generated applications. Existing applications are unaffected and do not need to make any changes. If you want to adopt these settings in an existing app, you can manually add them to your `config/initializers/react_on_rails.rb` file. [PR 2039](https://github.com/shakacode/react_on_rails/pull/2039) by [justin808](https://github.com/justin808).
 
+- **Removed Babel Dependency Installation**: The generator no longer installs `@babel/preset-react` or `@babel/preset-typescript` packages. Shakapacker handles JavaScript transpiler configuration (Babel, SWC, or esbuild) via the `javascript_transpiler` setting in `shakapacker.yml`. SWC is now the default transpiler and includes built-in support for React and TypeScript. Users who explicitly choose Babel will need to manually install and configure the required presets. This change reduces unnecessary dependencies and aligns with Shakapacker's modular transpiler approach. [PR <PLACEHOLDER>](https://github.com/shakacode/react_on_rails/pull/<PLACEHOLDER>) by [justin808](https://github.com/justin808).
+
 #### Documentation
 
 - **Simplified Configuration Files**: Improved configuration documentation and generator template for better clarity and usability. Reduced generator template from 67 to 42 lines (37% reduction). Added comprehensive testing configuration guide. Reorganized configuration docs into Essential vs Advanced sections. Enhanced Doctor program with diagnostics for server rendering and test compilation consistency. [PR #2011](https://github.com/shakacode/react_on_rails/pull/2011) by [justin808](https://github.com/justin808).

lib/generators/react_on_rails/js_dependency_manager.rb

@@ -2,6 +2,7 @@
 
 require_relative "generator_messages"
 
+# rubocop:disable Metrics/ModuleLength
 module ReactOnRails
   module Generators
     # Shared module for managing JavaScript dependencies across generators
@@ -11,11 +12,6 @@ module Generators
     # Since react_on_rails requires shakapacker, and shakapacker includes
     # package_json as a dependency, the package_json gem is always available.
     #
-    # == Instance Variables
-    # The module initializes and manages these instance variables:
-    # - @added_dependencies_to_package_json: Boolean tracking if package_json gem was used
-    #   (initialized by setup_js_dependencies using `unless defined?` pattern)
-    #
     # == Required Methods
     # Including classes must include GeneratorHelper module which provides:
     # - add_npm_dependencies(packages, dev: false): Add packages via package_json gem
@@ -29,10 +25,19 @@ module Generators
     #
     # == Installation Behavior
     # The module ALWAYS runs package manager install after adding dependencies.
-    # This is safe because package_json gem's install is idempotent - it only
+    # This is safe because package_json gem's install method is idempotent - it only
     # installs what's actually needed from package.json. This prevents edge cases
     # where package.json was modified but dependencies weren't installed.
     #
+    # == Error Handling
+    # All dependency addition methods use a tolerant error handling approach:
+    # - Return false on failure instead of raising exceptions
+    # - Catch StandardError and add warnings to GeneratorMessages
+    # - Provide clear manual installation instructions in warnings
+    # This provides better UX - the generator completes successfully even if
+    # dependency installation fails (e.g., network issues), and users can
+    # manually install dependencies afterward.
+    #
     # == Usage
     # Include this module in generator classes and call setup_js_dependencies
     # to handle all JS dependency installation via package_json gem.
@@ -91,9 +96,6 @@ module JsDependencyManager
       private
 
       def setup_js_dependencies
-        # Initialize instance variable if not already defined by including class
-        # This ensures safe operation when the module is first included
-        @added_dependencies_to_package_json = false unless defined?(@added_dependencies_to_package_json)
         add_js_dependencies
 
         # Always run install to ensure all dependencies are properly installed.
@@ -109,7 +111,7 @@ def add_js_dependencies
         add_react_dependencies
         add_css_dependencies
         # Rspack dependencies are only added when --rspack flag is used
-        add_rspack_dependencies if respond_to?(:options) && options.rspack?
+        add_rspack_dependencies if respond_to?(:options) && options&.rspack?
         # Dev dependencies vary based on bundler choice
         add_dev_dependencies
       end
@@ -128,92 +130,148 @@ def add_react_on_rails_package
                              end
 
         puts "Installing React on Rails package..."
-        if add_js_dependency(react_on_rails_pkg)
-          @added_dependencies_to_package_json = true
-        else
-          # This should not happen since package_json is always available via shakapacker
-          raise "Failed to add react-on-rails package via package_json gem. " \
-                "This indicates shakapacker dependency may not be properly installed."
-        end
+        return if add_package(react_on_rails_pkg)
+
+        # This should not happen since package_json is always available via shakapacker
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Failed to add react-on-rails package via package_json gem.
+
+          This indicates shakapacker dependency may not be properly installed.
+          You can install it manually by running:
+            npm install #{react_on_rails_pkg}
+        MSG
+      rescue StandardError => e
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Error adding react-on-rails package: #{e.message}
+
+          You can install it manually by running:
+            npm install #{react_on_rails_pkg}
+        MSG
       end
 
       def add_react_dependencies
         puts "Installing React dependencies..."
+        return if add_packages(REACT_DEPENDENCIES)
 
-        if add_js_dependencies_batch(REACT_DEPENDENCIES)
-          @added_dependencies_to_package_json = true
-        else
-          # This should not happen since package_json is always available via shakapacker
-          raise "Failed to add React dependencies (#{REACT_DEPENDENCIES.join(', ')}) via package_json gem. " \
-                "This indicates shakapacker dependency may not be properly installed."
-        end
+        # This should not happen since package_json is always available via shakapacker
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Failed to add React dependencies via package_json gem.
+
+          This indicates shakapacker dependency may not be properly installed.
+          You can install them manually by running:
+            npm install #{REACT_DEPENDENCIES.join(' ')}
+        MSG
+      rescue StandardError => e
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Error adding React dependencies: #{e.message}
+
+          You can install them manually by running:
+            npm install #{REACT_DEPENDENCIES.join(' ')}
+        MSG
       end
 
       def add_css_dependencies
         puts "Installing CSS handling dependencies..."
+        return if add_packages(CSS_DEPENDENCIES)
 
-        if add_js_dependencies_batch(CSS_DEPENDENCIES)
-          @added_dependencies_to_package_json = true
-        else
-          # This should not happen since package_json is always available via shakapacker
-          raise "Failed to add CSS dependencies (#{CSS_DEPENDENCIES.join(', ')}) via package_json gem. " \
-                "This indicates shakapacker dependency may not be properly installed."
-        end
+        # This should not happen since package_json is always available via shakapacker
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Failed to add CSS dependencies via package_json gem.
+
+          This indicates shakapacker dependency may not be properly installed.
+          You can install them manually by running:
+            npm install #{CSS_DEPENDENCIES.join(' ')}
+        MSG
+      rescue StandardError => e
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Error adding CSS dependencies: #{e.message}
+
+          You can install them manually by running:
+            npm install #{CSS_DEPENDENCIES.join(' ')}
+        MSG
       end
 
       def add_rspack_dependencies
         puts "Installing Rspack core dependencies..."
+        return if add_packages(RSPACK_DEPENDENCIES)
 
-        if add_js_dependencies_batch(RSPACK_DEPENDENCIES)
-          @added_dependencies_to_package_json = true
-        else
-          # This should not happen since package_json is always available via shakapacker
-          raise "Failed to add Rspack dependencies (#{RSPACK_DEPENDENCIES.join(', ')}) via package_json gem. " \
-                "This indicates shakapacker dependency may not be properly installed."
-        end
+        # This should not happen since package_json is always available via shakapacker
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Failed to add Rspack dependencies via package_json gem.
+
+          This indicates shakapacker dependency may not be properly installed.
+          You can install them manually by running:
+            npm install #{RSPACK_DEPENDENCIES.join(' ')}
+        MSG
+      rescue StandardError => e
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Error adding Rspack dependencies: #{e.message}
+
+          You can install them manually by running:
+            npm install #{RSPACK_DEPENDENCIES.join(' ')}
+        MSG
       end
 
       def add_typescript_dependencies
         puts "Installing TypeScript dependencies..."
+        return if add_packages(TYPESCRIPT_DEPENDENCIES, dev: true)
 
-        if add_js_dependencies_batch(TYPESCRIPT_DEPENDENCIES, dev: true)
-          @added_dependencies_to_package_json = true
-        else
-          # This should not happen since package_json is always available via shakapacker
-          raise "Failed to add TypeScript dependencies (#{TYPESCRIPT_DEPENDENCIES.join(', ')}) via package_json gem. " \
-                "This indicates shakapacker dependency may not be properly installed."
-        end
+        # This should not happen since package_json is always available via shakapacker
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Failed to add TypeScript dependencies via package_json gem.
+
+          This indicates shakapacker dependency may not be properly installed.
+          You can install them manually by running:
+            npm install --save-dev #{TYPESCRIPT_DEPENDENCIES.join(' ')}
+        MSG
+      rescue StandardError => e
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Error adding TypeScript dependencies: #{e.message}
+
+          You can install them manually by running:
+            npm install --save-dev #{TYPESCRIPT_DEPENDENCIES.join(' ')}
+        MSG
       end
 
       def add_dev_dependencies
         puts "Installing development dependencies..."
 
         # Use Rspack-specific dev dependencies if --rspack flag is set
-        dev_deps = if respond_to?(:options) && options.rspack?
+        dev_deps = if respond_to?(:options) && options&.rspack?
                      RSPACK_DEV_DEPENDENCIES
                    else
                      DEV_DEPENDENCIES
                    end
 
-        if add_js_dependencies_batch(dev_deps, dev: true)
-          @added_dependencies_to_package_json = true
-        else
-          # This should not happen since package_json is always available via shakapacker
-          raise "Failed to add development dependencies (#{dev_deps.join(', ')}) via package_json gem. " \
-                "This indicates shakapacker dependency may not be properly installed."
-        end
+        return if add_packages(dev_deps, dev: true)
+
+        # This should not happen since package_json is always available via shakapacker
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Failed to add development dependencies via package_json gem.
+
+          This indicates shakapacker dependency may not be properly installed.
+          You can install them manually by running:
+            npm install --save-dev #{dev_deps.join(' ')}
+        MSG
+      rescue StandardError => e
+        GeneratorMessages.add_warning(<<~MSG.strip)
+          ⚠️  Error adding development dependencies: #{e.message}
+
+          You can install them manually by running:
+            npm install --save-dev #{dev_deps.join(' ')}
+        MSG
       end
 
       # Add a single dependency using package_json gem
       #
       # This method is used internally for adding the react-on-rails package
       # with version-specific handling (react-on-rails@VERSION).
-      # For batch operations, use add_js_dependencies_batch instead.
+      # For batch operations, use add_packages instead.
       #
       # @param package [String] Package specifier (e.g., "react-on-rails@16.0.0")
       # @param dev [Boolean] Whether to add as dev dependency
       # @return [Boolean] true if successful, false otherwise
-      def add_js_dependency(package, dev: false)
+      def add_package(package, dev: false)
         pj = package_json
         return false unless pj
 
@@ -240,7 +298,7 @@ def add_js_dependency(package, dev: false)
       # @param packages [Array<String>] Package names to add
       # @param dev [Boolean] Whether to add as dev dependencies
       # @return [Boolean] true if successful, false otherwise
-      def add_js_dependencies_batch(packages, dev: false)
+      def add_packages(packages, dev: false)
         # Use the add_npm_dependencies helper from GeneratorHelper
         add_npm_dependencies(packages, dev: dev)
       end
@@ -270,3 +328,4 @@ def install_js_dependencies
     end
   end
 end
+# rubocop:enable Metrics/ModuleLength