From cdeb96609b17aa7c7d9bd62b3692ab41a14bad04 Mon Sep 17 00:00:00 2001
From: Ross Becker <ross.becker@gmail.com>
Date: Fri, 10 Feb 2023 09:16:17 -0800
Subject: [PATCH 1/2] add support for nested attribute hashes rendered as
 hyphen separated flat attributes

---
 lib/arbre/html/attributes.rb                | 14 +++++-
 spec/arbre/unit/html/tag_attributes_spec.rb | 48 ++++++++++++++++++---
 2 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/lib/arbre/html/attributes.rb b/lib/arbre/html/attributes.rb
index d216b43d..8fd92bf6 100644
--- a/lib/arbre/html/attributes.rb
+++ b/lib/arbre/html/attributes.rb
@@ -5,7 +5,7 @@ module HTML
     class Attributes < Hash
 
       def to_s
-        map do |name, value|
+        flatten_hash.map do |name, value|
           next if value_empty?(value)
           "#{html_escape(name)}=\"#{html_escape(value)}\""
         end.compact.join ' '
@@ -17,6 +17,18 @@ def any?
 
       protected
 
+      def flatten_hash(hash = self, old_path = [], accumulator = {})
+        hash.each do |key, value|
+          path = old_path + [key]
+          if value.is_a? Hash
+            flatten_hash(value, path, accumulator)
+          else
+            accumulator[path.join('-')] = value
+          end
+        end
+        accumulator
+      end
+
       def value_empty?(value)
         value.respond_to?(:empty?) ? value.empty? : !value
       end
diff --git a/spec/arbre/unit/html/tag_attributes_spec.rb b/spec/arbre/unit/html/tag_attributes_spec.rb
index b41e983e..8798a0d6 100644
--- a/spec/arbre/unit/html/tag_attributes_spec.rb
+++ b/spec/arbre/unit/html/tag_attributes_spec.rb
@@ -13,16 +13,50 @@
       expect(tag.attributes).to eq({id: "my_id"})
     end
 
-    it "should render the attributes to html" do
-      expect(tag.to_s).to eq "<tag id=\"my_id\"></tag>\n"
+    describe "#to_s" do
+      it "should render the attributes to html" do
+        expect(tag.to_s).to eq "<tag id=\"my_id\"></tag>\n"
+      end
+
+      it "shouldn't render attributes that are empty" do
+        tag.class_list # initializes an empty ClassList
+        tag.set_attribute :foo, ''
+        tag.set_attribute :bar, nil
+
+        expect(tag.to_s).to eq "<tag id=\"my_id\"></tag>\n"
+      end
+
+      context "when there is a nested attribute" do
+        before { tag.build id: "my_id", data: { action: 'some_action' } }
+
+        it "should flatten the attributes when rendering to html" do
+          expect(tag.to_s).to eq "<tag id=\"my_id\" data-action=\"some_action\"></tag>\n"
+        end
+
+        it "shouldn't render attributes that are empty" do
+          tag.class_list # initializes an empty ClassList
+          tag.set_attribute :foo, { bar: '' }
+          tag.set_attribute :bar, { baz: nil }
+
+          expect(tag.to_s).to eq "<tag id=\"my_id\" data-action=\"some_action\"></tag>\n"
+        end
+      end
+    end
+
+    context "when there is a deeply nested attribute" do
+      before { tag.build id: "my_id", foo: { bar: { baz: 'foozle' } } }
+
+      it "should flatten the attributes when rendering to html" do
+        expect(tag.to_s).to eq "<tag id=\"my_id\" foo-bar-baz=\"foozle\"></tag>\n"
+      end
     end
 
-    it "shouldn't render attributes that are empty" do
-      tag.class_list # initializes an empty ClassList
-      tag.set_attribute :foo, ''
-      tag.set_attribute :bar, nil
+    context "when there are multiple nested attributes" do
+      before { tag.build id: "my_id", foo: { bar: 'foozle1', baz: 'foozle2' } }
 
-      expect(tag.to_s).to eq "<tag id=\"my_id\"></tag>\n"
+      it "should flatten the attributes when rendering to html" do
+        expect(tag.to_s).to eq "<tag id=\"my_id\" foo-bar=\"foozle1\" foo-baz=\"foozle2\"></tag>\n"
+      end
     end
 
     it "should get an attribute value" do

From faf4f99f7925d61f8424739cb2fbf8c6c5e68e0c Mon Sep 17 00:00:00 2001
From: Ross Becker <ross.becker@gmail.com>
Date: Fri, 10 Feb 2023 17:36:55 -0800
Subject: [PATCH 2/2] move two more tests inside #to_s context

---
 spec/arbre/unit/html/tag_attributes_spec.rb | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/spec/arbre/unit/html/tag_attributes_spec.rb b/spec/arbre/unit/html/tag_attributes_spec.rb
index 8798a0d6..19b9c6d5 100644
--- a/spec/arbre/unit/html/tag_attributes_spec.rb
+++ b/spec/arbre/unit/html/tag_attributes_spec.rb
@@ -41,21 +41,21 @@
           expect(tag.to_s).to eq "<tag id=\"my_id\" data-action=\"some_action\"></tag>\n"
         end
       end
-    end
 
-    context "when there is a deeply nested attribute" do
-      before { tag.build id: "my_id", foo: { bar: { baz: 'foozle' } } }
+      context "when there is a deeply nested attribute" do
+        before { tag.build id: "my_id", foo: { bar: { baz: 'foozle' } } }
 
-      it "should flatten the attributes when rendering to html" do
-        expect(tag.to_s).to eq "<tag id=\"my_id\" foo-bar-baz=\"foozle\"></tag>\n"
+        it "should flatten the attributes when rendering to html" do
+          expect(tag.to_s).to eq "<tag id=\"my_id\" foo-bar-baz=\"foozle\"></tag>\n"
+        end
       end
-    end
 
-    context "when there are multiple nested attributes" do
-      before { tag.build id: "my_id", foo: { bar: 'foozle1', baz: 'foozle2' } }
+      context "when there are multiple nested attributes" do
+        before { tag.build id: "my_id", foo: { bar: 'foozle1', baz: 'foozle2' } }
 
-      it "should flatten the attributes when rendering to html" do
-        expect(tag.to_s).to eq "<tag id=\"my_id\" foo-bar=\"foozle1\" foo-baz=\"foozle2\"></tag>\n"
+        it "should flatten the attributes when rendering to html" do
+          expect(tag.to_s).to eq "<tag id=\"my_id\" foo-bar=\"foozle1\" foo-baz=\"foozle2\"></tag>\n"
+        end
       end
     end