From f988079d0ba601cbc5c368de3addf0d5e7b64779 Mon Sep 17 00:00:00 2001
From: Kazuki Nishikawa <kz.nishikawa@gmail.com>
Date: Wed, 24 Dec 2025 17:31:54 +0900
Subject: [PATCH 1/2] Support ERB whitespace trimming tag

fixes: #335
---
 lib/rufo/erb_formatter.rb           |  2 +-
 spec/lib/rufo/erb_formatter_spec.rb | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/lib/rufo/erb_formatter.rb b/lib/rufo/erb_formatter.rb
index 49cd390d..3f146c45 100644
--- a/lib/rufo/erb_formatter.rb
+++ b/lib/rufo/erb_formatter.rb
@@ -8,7 +8,7 @@ def initialize(src)
   end
 
   def stags
-    ["<%==", "<%+={0,2}"] + super
+    ["<%-", "<%==", "<%+={0,2}"] + super
   end
 
   def etags
diff --git a/spec/lib/rufo/erb_formatter_spec.rb b/spec/lib/rufo/erb_formatter_spec.rb
index 9ad8816c..3820a049 100644
--- a/spec/lib/rufo/erb_formatter_spec.rb
+++ b/spec/lib/rufo/erb_formatter_spec.rb
@@ -99,5 +99,25 @@
       result = subject.format("<% # TODO: fix this later %>")
       expect(result).to eql("<% # TODO: fix this later %>")
     end
+
+    it "handles leading whitespace trim tag" do
+      result = subject.format('<%- if controller_name != "sessions" %>')
+      expect(result).to eql('<%- if controller_name != "sessions" %>')
+    end
+
+    it "handles trailing whitespace trim tag" do
+      result = subject.format('<% if controller_name != "sessions" -%>')
+      expect(result).to eql('<% if controller_name != "sessions" -%>')
+    end
+
+    it "handles both whitespace trim tag" do
+      result = subject.format('<%- if controller_name != "sessions" -%>')
+      expect(result).to eql('<%- if controller_name != "sessions" -%>')
+    end
+
+    it "handles minus unary operator" do
+      result = subject.format('<% - x * y %>')
+      expect(result).to eql('<% -x * y %>')
+    end
   end
 end

From fd0fd15d3d72cd5831167ca64dee9a979f129f43 Mon Sep 17 00:00:00 2001
From: Kazuki Nishikawa <kz.nishikawa@gmail.com>
Date: Wed, 24 Dec 2025 17:41:04 +0900
Subject: [PATCH 2/2] format with rufo

---
 spec/lib/rufo/erb_formatter_spec.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/spec/lib/rufo/erb_formatter_spec.rb b/spec/lib/rufo/erb_formatter_spec.rb
index 3820a049..f00ed0ba 100644
--- a/spec/lib/rufo/erb_formatter_spec.rb
+++ b/spec/lib/rufo/erb_formatter_spec.rb
@@ -116,8 +116,8 @@
     end
 
     it "handles minus unary operator" do
-      result = subject.format('<% - x * y %>')
-      expect(result).to eql('<% -x * y %>')
+      result = subject.format("<% - x * y %>")
+      expect(result).to eql("<% -x * y %>")
     end
   end
 end