Add component convenience method

lib/operations/convenience.rb

@@ -83,20 +83,21 @@ def contract(prefix = nil, from: OperationContract, &block)
     const_set(:"#{prefix.to_s.camelize}Contract", contract)
   end
 
-  %w[policy precondition callback].each do |kind|
-    define_method kind do |prefix = nil, from: Object, &block|
-      raise ArgumentError.new("Please provide either a superclass or a block for #{kind}") unless from || block
-
-      klass = Class.new(from)
+  def component(name, from: Object, dry_initializer: false, dry_monads_result: false, &block) # rubocop:disable Metrics/CyclomaticComplexity
+    raise ArgumentError.new("Please provide either a superclass or a block for #{name}") unless from || block
 
-      if from == Object
-        klass.extend(Dry::Initializer)
-        klass.include(Dry::Monads[:result])
-      end
+    klass = Class.new(from)
+    klass.extend(Dry::Initializer) if dry_initializer && !klass.include?(Dry::Initializer) # rubocop:disable Rails/NegateInclude
+    klass.include(Dry::Monads[:result]) if dry_monads_result && !klass.is_a?(Dry::Monads[:result])
+    klass.define_method(:call, &block) if block
 
-      klass.define_method(:call, &block) if block
+    const_set(name.to_s.camelize, klass)
+  end
 
-      const_set(:"#{prefix.to_s.camelize}#{kind.camelize}", klass)
+  %w[policy precondition callback].each do |kind|
+    define_method kind do |prefix = nil, from: Object, &block|
+      component([prefix, kind].compact_blank.join("_"), from: from,
+        dry_initializer: true, dry_monads_result: true, &block)
     end
   end
 end

spec/operations/convenience_spec.rb

@@ -66,12 +66,39 @@ def self.default(arg)
     end
   end
 
+  describe "#component" do
+    subject(:component) { dummy_operation.component(name, **options) { :foobar } }
+
+    let(:name) { :custom_hydrator }
+    let(:options) { {} }
+
+    specify do
+      expect(component.name).to eq("DummyOperation::CustomHydrator")
+      expect(component).not_to be_a(Dry::Initializer)
+      expect(component).not_to include(Dry::Monads[:result])
+      expect(component.new.call).to eq(:foobar)
+    end
+
+    context "with options given" do
+      let(:options) { { dry_initializer: true, dry_monads_result: true } }
+
+      specify do
+        expect(component.name).to eq("DummyOperation::CustomHydrator")
+        expect(component).to be_a(Dry::Initializer)
+        expect(component).to include(Dry::Monads[:result])
+        expect(component.new.call).to eq(:foobar)
+      end
+    end
+  end
+
   %w[policy precondition callback].each do |kind|
     describe "##{kind}" do
       subject(:component) { dummy_operation.public_send(kind) { :foobar } }
 
       specify do
         expect(component.name).to eq("DummyOperation::#{kind.camelize}")
+        expect(component).to be_a(Dry::Initializer)
+        expect(component).to include(Dry::Monads[:result])
         expect(component.new.call).to eq(:foobar)
       end
 
@@ -89,6 +116,8 @@ def other_method
         specify do
           expect(component.name).to eq("DummyOperation::#{kind.camelize}")
           expect(component).to be < parent
+          expect(component).to be_a(Dry::Initializer)
+          expect(component).to include(Dry::Monads[:result])
           expect(component.new.call).to eq(:foobar)
         end
       end