FEATURE: upgrade sprockets to latest stable

This unlocks Rails upgrades, so we can now upgrade to latest Rails

Gemfile.lock

@@ -358,10 +358,10 @@ GEM
     spork-rails (4.0.0)
       rails (>= 3.0.0, < 5)
       spork (>= 1.0rc0)
-    sprockets (3.6.3)
+    sprockets (3.7.1)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
-    sprockets-rails (3.1.1)
+    sprockets-rails (3.2.0)
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)

lib/es6_module_transpiler/sprockets.rb

@@ -1,3 +1,4 @@
 require 'sprockets'
 
-Sprockets.register_engine '.es6', Tilt::ES6ModuleTranspilerTemplate
+Sprockets.register_mime_type 'application/ecmascript6', extensions: ['.es6', '.js.es6'], charset: :unicode
+Sprockets.register_transformer 'application/ecmascript6', 'application/javascript', Tilt::ES6ModuleTranspilerTemplate

lib/es6_module_transpiler/tilt/es6_module_transpiler_template.rb

@@ -10,6 +10,15 @@ module Tilt
     @mutex = Mutex.new
     @ctx_init = Mutex.new
 
+    def self.call(input)
+      filename = input[:filename]
+      source = input[:data]
+      context = input[:environment].context_class.new(input)
+
+      result = new(filename){source}.render(context)
+      context.metadata.merge(data: result)
+    end
+
     def prepare
       # intentionally left empty
       # Tilt requires this method to be defined

lib/source_url.rb

@@ -1,6 +1,15 @@
 class SourceURL < Tilt::Template
   self.default_mime_type = 'application/javascript'
 
+  def self.call(input)
+    filename = input[:filename]
+    source = input[:data]
+    context = input[:environment].context_class.new(input)
+
+    result = new(filename){source}.render(context)
+    context.metadata.merge(data: result)
+  end
+
   def prepare
   end