Deprecate usage of positional argument for slot in render

Author: javierav

lib/class_variants/instance.rb

@@ -34,7 +34,13 @@ def merge(**options, &block)
       self
     end
 
-    def render(slot = :default, **overrides)
+    def render(slot = nil, **overrides)
+      warn <<~MSG if slot
+        (ClassVariants) DEPRECATION WARNING: Use of positional argument for slot in render is deprecated
+        and will be removed in the next version. Use the `slot` keyword argument instead.
+      MSG
+
+      slot = overrides.fetch(:slot, slot || :default)
       classes = overrides.delete(:class)
       result = []
 

readme.md

@@ -81,6 +81,8 @@ button_classes.render
 button_classes.render(color: :red, size: :xl, icon: true)
 ```
 
+> **Note**: `slot` and `class` are reserved words and cannot be used as variants keys! Continue reading for usage.
+
 ## Compound Variants
 
 ```ruby
@@ -177,10 +179,10 @@ end
 
 ```erb
 <div>
-  <div class="<%= alert_classes.render(:head) %>">
+  <div class="<%= alert_classes.render(slot: :head) %>">
     Head of alert
   </div>
-  <div class="<%= alert_classes.render(:body) %>">
+  <div class="<%= alert_classes.render(slot: :body) %>">
     Body of alert
   </div>
 </div>
@@ -262,19 +264,19 @@ alert_classes.render
 alert_classes.render(color: :red)
 
 # render slot with defaults variants
-alert_classes.render(:body)
+alert_classes.render(slot: :body)
 
 # render slot with custom variants
-alert_classes.render(:body, color: :red)
+alert_classes.render(slot: :body, color: :red)
 
-# if slot not exist, throw error? return empty classes?
-alert_classes.render(:non_existent_slot, color: :red)
+# if slot not exist, return empty classes
+alert_classes.render(slot: :non_existent_slot, color: :red)
 
 # render default slot with custom class (will be merged)
 alert_classes.render(class: "...")
 
 # render slot with custom class (will be merged)
-alert_classes.render(:body, class: "...")
+alert_classes.render(slot: :body, class: "...")
 ```
 
 ## Use with Rails

test/merge_test.rb

@@ -65,7 +65,7 @@ def test_block_merge
       defaults variant: :filled
     end
 
-    assert_equal "rounded mb-4 bg-red-100 dark:bg-red-800", cv.render(:root)
-    assert_equal "font-bold mb-1 text-red-900 dark:text-red-50", cv.render(:title)
+    assert_equal "rounded mb-4 bg-red-100 dark:bg-red-800", cv.render(slot: :root)
+    assert_equal "font-bold mb-1 text-red-900 dark:text-red-50", cv.render(slot: :title)
   end
 end

test/slot_test.rb

@@ -45,25 +45,25 @@ def test_render_default_slot
   end
 
   def test_render_nonexistent_slot
-    assert_equal "", @cv.render(:nonexistent)
+    assert_equal "", @cv.render(slot: :nonexistent)
   end
 
   def test_render_slot_with_defaults
-    assert_equal "rounded py-3 px-5 mb-4 bg-green-100 dark:bg-green-800", @cv.render(:root)
+    assert_equal "rounded py-3 px-5 mb-4 bg-green-100 dark:bg-green-800", @cv.render(slot: :root)
   end
 
   def test_render_slot_with_variant
-    assert_equal "rounded py-3 px-5 mb-4 border border-green-700 dark:border-green-500", @cv.render(:root, variant: :outlined)
+    assert_equal "rounded py-3 px-5 mb-4 border border-green-700 dark:border-green-500", @cv.render(slot: :root, variant: :outlined)
   end
 
   def test_render_slot_without_base
-    assert_equal "text-green-700 dark:text-green-200", @cv.render(:message)
+    assert_equal "text-green-700 dark:text-green-200", @cv.render(slot: :message)
   end
 
   def test_render_slot_with_unused_variant
     assert_equal(
       "rounded py-3 px-5 mb-4 border border-green-700 dark:border-green-500",
-      @cv.render(:root, variant: :outlined, type: :button)
+      @cv.render(slot: :root, variant: :outlined, type: :button)
     )
   end
 end