Merge pull request #2411 from jsolas/add-activesupport-notifications-to-compiler-

Add after_compile hook for component extensions

Author: joelhawksley

docs/CHANGELOG.md

@@ -10,6 +10,10 @@ nav_order: 6
 
 ## main
 
+* Add `after_compile` class method hook to enable extensions to run logic after component compilation.
+
+    *Jose Solás*
+
 * Fix outdated reference to preview layout configuration in docs.
 
     *Lucas Geron*

lib/view_component/base.rb

@@ -610,6 +610,16 @@ def __vc_compiled?
         __vc_compiler.compiled?
       end
 
+      # Hook called by the compiler after a component is compiled.
+      #
+      # Extensions can override this class method to run logic after
+      # compilation (e.g., generate helpers, register metadata, etc.).
+      #
+      # By default, this is a no-op.
+      def after_compile
+        # no-op by default
+      end
+
       # @private
       def __vc_ensure_compiled
         __vc_compile unless __vc_compiled?

lib/view_component/compiler.rb

@@ -52,6 +52,8 @@ def compile(raise_errors: false, force: false)
         @component.__vc_build_i18n_backend
 
         CompileCache.register(@component)
+
+        @component.after_compile
       end
     end
 

test/sandbox/test/base_test.rb

@@ -195,4 +195,63 @@ def test_uses_module_configuration
     assert_equal false, TestAlreadyConfigurableModule::SomeComponent.instrumentation_enabled
     assert_equal false, TestAlreadyConfiguredModule::SomeComponent.instrumentation_enabled
   end
+
+  def test_after_compile_hook_called_on_compile
+    klass = Class.new(ViewComponent::Base) do
+      @@calls = 0
+
+      def self.calls
+        @@calls
+      end
+
+      class << self
+        def after_compile
+          @@calls += 1
+        end
+      end
+
+      erb_template ""
+    end
+
+    self.class.const_set(:TempHookComponent, klass)
+    ViewComponent::CompileCache.invalidate_class!(klass)
+
+    ViewComponent::Compiler.new(klass).compile(force: true)
+    assert_equal 1, klass.calls
+  ensure
+    self.class.send(:remove_const, :TempHookComponent) if self.class.const_defined?(:TempHookComponent)
+    ViewComponent::CompileCache.invalidate_class!(klass) if defined?(klass)
+  end
+
+  def test_after_compile_not_called_on_cached_compile
+    klass = Class.new(ViewComponent::Base) do
+      @@calls = 0
+
+      def self.calls
+        @@calls
+      end
+
+      class << self
+        def after_compile
+          @@calls += 1
+        end
+      end
+
+      erb_template ""
+    end
+
+    self.class.const_set(:TempHookCachedComponent, klass)
+    ViewComponent::CompileCache.invalidate_class!(klass)
+
+    compiler = ViewComponent::Compiler.new(klass)
+    compiler.compile(force: true)
+    assert_equal 1, klass.calls
+
+    # compile again without force -> should not call hook again
+    compiler.compile
+    assert_equal 1, klass.calls
+  ensure
+    self.class.send(:remove_const, :TempHookCachedComponent) if self.class.const_defined?(:TempHookCachedComponent)
+    ViewComponent::CompileCache.invalidate_class!(klass) if defined?(klass)
+  end
 end