From 9dfe74c15b68090941efdfeba8a1f0711aa0a8c7 Mon Sep 17 00:00:00 2001
From: Richard Macklin <richard.github@nrm.com>
Date: Fri, 23 Sep 2016 01:00:05 -0700
Subject: [PATCH] Add cache_key to BabelProcessor

This ensures the cache will be invalidated if the options are changed.
---
 lib/sprockets/babel_processor.rb |  6 ++++++
 test/test_babel_processor.rb     | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/lib/sprockets/babel_processor.rb b/lib/sprockets/babel_processor.rb
index c0c140831..e3bebc959 100644
--- a/lib/sprockets/babel_processor.rb
+++ b/lib/sprockets/babel_processor.rb
@@ -16,6 +16,12 @@ def self.call(input)
       instance.call(input)
     end
 
+    def self.cache_key
+      instance.cache_key
+    end
+
+    attr_reader :cache_key
+
     def initialize(options = {})
       @options = options.merge({
         'blacklist' => (options['blacklist'] || []) + ['useStrict'],
diff --git a/test/test_babel_processor.rb b/test/test_babel_processor.rb
index 7277e35ec..4d8f72442 100644
--- a/test/test_babel_processor.rb
+++ b/test/test_babel_processor.rb
@@ -168,4 +168,15 @@ def test_caching_takes_filename_into_account
 });
     JS
   end
+
+  def test_cache_key
+    assert Sprockets::BabelProcessor.cache_key
+
+    amd_processor_1 = Sprockets::BabelProcessor.new('modules' => 'amd')
+    amd_processor_2 = Sprockets::BabelProcessor.new('modules' => 'amd')
+    assert_equal amd_processor_1.cache_key, amd_processor_2.cache_key
+
+    system_processor = Sprockets::BabelProcessor.new('modules' => 'system')
+    refute_equal amd_processor_1.cache_key, system_processor.cache_key
+  end
 end