From c8e08d2717b98a2268da89f8196fdb1eb93725bf Mon Sep 17 00:00:00 2001
From: Samuel Williams <samuel.williams@oriontransfer.co.nz>
Date: Thu, 20 Feb 2020 16:12:42 +1300
Subject: [PATCH] `Hash#slice!` was not implemented as I expected.

---
 .travis.yml                     | 1 +
 lib/trenni/sanitize/filter.rb   | 4 ++++
 lib/trenni/sanitize/fragment.rb | 6 ++++--
 trenni-sanitize.gemspec         | 2 +-
 4 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index cf0513e..ec78a16 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,6 +4,7 @@ cache: bundler
 
 matrix:
   include:
+    - rvm: 2.4
     - rvm: 2.5
     - rvm: 2.6
     - rvm: 2.6
diff --git a/lib/trenni/sanitize/filter.rb b/lib/trenni/sanitize/filter.rb
index 3f93b7b..1a2c5c9 100644
--- a/lib/trenni/sanitize/filter.rb
+++ b/lib/trenni/sanitize/filter.rb
@@ -66,6 +66,10 @@ def accept!(mode = ALL)
 				def [] key
 					self.tag&.attributes[key]
 				end
+				
+				def limit_attributes(keys)
+					self.tag&.attributes&.select!{|key, value| keys.include?(key)}
+				end
 			end
 			
 			def initialize(output, entities)
diff --git a/lib/trenni/sanitize/fragment.rb b/lib/trenni/sanitize/fragment.rb
index cafc02a..2830a72 100644
--- a/lib/trenni/sanitize/fragment.rb
+++ b/lib/trenni/sanitize/fragment.rb
@@ -20,10 +20,12 @@
 
 require_relative 'filter'
 
+require 'set'
+
 module Trenni
 	module Sanitize
 		class Fragment < Filter
-			STANDARD_ATTRIBUTES = ['class', 'style'].freeze
+			STANDARD_ATTRIBUTES = Set.new(['class', 'style']).freeze
 			
 			ALLOWED_TAGS = {
 				'div' => STANDARD_ATTRIBUTES,
@@ -49,7 +51,7 @@ class Fragment < Filter
 			
 			def filter(node)
 				if attributes = ALLOWED_TAGS[node.name]
-					node.tag.attributes.slice!(*attributes)
+					node.limit_attributes(attributes)
 					
 					node.accept!
 				else
diff --git a/trenni-sanitize.gemspec b/trenni-sanitize.gemspec
index c06fe9f..3a07197 100644
--- a/trenni-sanitize.gemspec
+++ b/trenni-sanitize.gemspec
@@ -15,7 +15,7 @@ Gem::Specification.new do |spec|
 	spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
 	spec.require_paths = ["lib"]
 	
-	spec.required_ruby_version = '~> 2.5'
+	spec.required_ruby_version = '~> 2.4'
 	
 	spec.add_dependency "trenni", '~> 3.5'