Add support for subclass inheritance in helper

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## Unreleased
 - Add support for merging ([#23](https://github.com/avo-hq/class_variants/pull/23))
+- Add support for subclass inheritance in helper ([#24](https://github.com/avo-hq/class_variants/pull/24))
 
 ## 1.0.0 (2024-11-13)
 - Add support for slots ([#15](https://github.com/avo-hq/class_variants/pull/15))

lib/class_variants/helper.rb

@@ -2,22 +2,22 @@ module ClassVariants
   module Helper
     module ClassMethods
       def class_variants(...)
-        @_class_variants_instance = ClassVariants.build(...)
-      end
-
-      def _class_variants_instance
-        @_class_variants_instance
+        singleton_class.instance_variable_get(:@_class_variants_instance).merge(...)
       end
     end
 
     def self.included(base)
       base.extend(ClassMethods)
+      base.singleton_class.instance_variable_set(:@_class_variants_instance, ClassVariants::Instance.new)
+      base.define_singleton_method(:inherited) do |subclass|
+        subclass.singleton_class.instance_variable_set(
+          :@_class_variants_instance, base.singleton_class.instance_variable_get(:@_class_variants_instance).dup
+        )
+      end
     end
 
     def class_variants(...)
-      raise "You must configure class_variants in class definition" unless self.class._class_variants_instance
-
-      self.class._class_variants_instance.render(...)
+      self.class.singleton_class.instance_variable_get(:@_class_variants_instance).render(...)
     end
   end
 end

lib/class_variants/instance.rb

@@ -8,6 +8,14 @@ def initialize(...)
       merge(...)
     end
 
+    def dup
+      self.class.new.tap do |copy|
+        copy.instance_variable_set(:@bases, @bases.dup)
+        copy.instance_variable_set(:@variants, @variants.dup)
+        copy.instance_variable_set(:@defaults, @defaults.dup)
+      end
+    end
+
     def merge(**options, &block)
       raise ArgumentError, "Use of hash config and code block is not supported" if !options.empty? && block_given?
 

test/helper_test.rb

@@ -7,7 +7,15 @@ class DemoClass
     class_variants base: "rounded border"
   end
 
+  class Subclass < DemoClass
+    class_variants base: "bg-black"
+  end
+
   def test_call_from_instance
     assert_equal "rounded border", DemoClass.new.class_variants
   end
+
+  def test_call_from_subclass
+    assert_equal "rounded border bg-black", Subclass.new.class_variants
+  end
 end