From 8accf97b6f5fb76942b03279a3af6fa6210f18db Mon Sep 17 00:00:00 2001
From: Javier Aranda <javier@aranda.dev>
Date: Thu, 17 Oct 2024 14:48:26 +0200
Subject: [PATCH] Add support for TailwindMerge

---
 CHANGELOG.md                   |  1 +
 Gemfile                        |  1 +
 Gemfile.lock                   |  4 ++++
 lib/class_variants.rb          | 21 +++++++++++++++++++++
 lib/class_variants/instance.rb | 10 +++++++++-
 test/configuration_test.rb     | 25 +++++++++++++++++++++++++
 test/tailwind_merger_test.rb   | 21 +++++++++++++++++++++
 7 files changed, 82 insertions(+), 1 deletion(-)
 create mode 100644 test/configuration_test.rb
 create mode 100644 test/tailwind_merger_test.rb

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e39c1a2..7eaca5d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
 ## Unreleased
+- Add support for TailwindMerge
 
 ## 0.0.7 (2023-12-07)
 - Add support for compound variants ([#8](https://github.com/avo-hq/class_variants/pull/8))
diff --git a/Gemfile b/Gemfile
index c5687eb..b3ca7c2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,3 +11,4 @@ gem "rubocop-minitest", require: false
 gem "rubocop-rake", require: false
 gem "standard", ">= 1.35.1", require: false
 gem "standard-performance", require: false
+gem "tailwind_merge"
diff --git a/Gemfile.lock b/Gemfile.lock
index 2194e32..1833b40 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -15,6 +15,7 @@ GEM
     json (2.7.2)
     language_server-protocol (3.17.0.3)
     lint_roller (1.1.0)
+    lru_redux (1.1.0)
     minitest (5.25.1)
     parallel (1.26.3)
     parser (3.3.5.0)
@@ -64,6 +65,8 @@ GEM
       lint_roller (~> 1.1)
       rubocop-performance (~> 1.22.0)
     stringio (3.1.1)
+    tailwind_merge (0.13.1)
+      lru_redux (~> 1.1)
     unicode-display_width (2.6.0)
 
 PLATFORMS
@@ -81,6 +84,7 @@ DEPENDENCIES
   rubocop-rake
   standard (>= 1.35.1)
   standard-performance
+  tailwind_merge
 
 BUNDLED WITH
    2.5.20
diff --git a/lib/class_variants.rb b/lib/class_variants.rb
index 6b0a21d..2d62dc2 100644
--- a/lib/class_variants.rb
+++ b/lib/class_variants.rb
@@ -4,9 +4,30 @@
 require "class_variants/railtie" if defined?(Rails)
 
 module ClassVariants
+  Configuration = Struct.new(:tw_merge, :tw_merge_config)
+
+  @mutex = Mutex.new
+
   class << self
+    def configuration
+      @configuration ||= Configuration.new(tw_merge: false, tw_merge_config: {})
+    end
+
+    def configure(&block)
+      yield(configuration)
+    end
+
     def build(classes, **args)
       Instance.new classes, **args
     end
+
+    def tailwind_merge
+      @mutex.synchronize do
+        @tailwind_merge ||= begin
+          require "tailwind_merge"
+          TailwindMerge::Merger.new(config: configuration.tw_merge_config)
+        end
+      end
+    end
   end
 end
diff --git a/lib/class_variants/instance.rb b/lib/class_variants/instance.rb
index 2ee5cdc..2549ce2 100644
--- a/lib/class_variants/instance.rb
+++ b/lib/class_variants/instance.rb
@@ -33,7 +33,7 @@ def render(**overrides)
       result.compact!
 
       # Return the final token list
-      result.join " "
+      with_tailwind_merge(result.join(" "))
     end
 
     private
@@ -53,5 +53,13 @@ def expand_boolean_variants(variants)
         output.merge!(next_variant) { |_key, v1, v2| v1.merge!(v2) }
       end
     end
+
+    def with_tailwind_merge(classes)
+      if ClassVariants.configuration.tw_merge
+        ClassVariants.tailwind_merge.merge(classes)
+      else
+        classes
+      end
+    end
   end
 end
diff --git a/test/configuration_test.rb b/test/configuration_test.rb
new file mode 100644
index 0000000..4798906
--- /dev/null
+++ b/test/configuration_test.rb
@@ -0,0 +1,25 @@
+require "test_helper"
+
+class ConfigurationTest < Minitest::Test
+  def teardown
+    ClassVariants.configure do |config|
+      config.tw_merge = false
+    end
+  end
+
+  def test_configuration_tw_merge_default
+    refute ClassVariants.configuration.tw_merge
+  end
+
+  def test_configuration_tw_merge_config_default
+    assert_empty ClassVariants.configuration.tw_merge_config
+  end
+
+  def test_configure
+    ClassVariants.configure do |config|
+      config.tw_merge = true
+    end
+
+    assert ClassVariants.configuration.tw_merge
+  end
+end
diff --git a/test/tailwind_merger_test.rb b/test/tailwind_merger_test.rb
new file mode 100644
index 0000000..272e7a5
--- /dev/null
+++ b/test/tailwind_merger_test.rb
@@ -0,0 +1,21 @@
+require "test_helper"
+
+class TailwindMergerTest < Minitest::Test
+  def teardown
+    ClassVariants.configure do |config|
+      config.tw_merge = false
+    end
+  end
+
+  def test_without_tw_merge
+    assert_equal "border rounded px-2 py-1 p-5", ClassVariants.build("border rounded px-2 py-1 p-5").render
+  end
+
+  def test_with_tw_merge
+    ClassVariants.configure do |config|
+      config.tw_merge = true
+    end
+
+    assert_equal "border rounded p-5", ClassVariants.build("border rounded px-2 py-1 p-5").render
+  end
+end