Removed Sprockets support. I suggest using a client-side tool like StealJS or RequireJS

Rakefile

@@ -17,7 +17,6 @@ begin
     gem.add_dependency("thin",                "~>1.2.0")
     gem.add_dependency("shotgun",             "~>0.8.0")
     gem.add_dependency("templater",           "~>1.0.0")
-    gem.add_dependency("sprockets",           "~>1.0.0")
     gem.add_dependency("sinatra",             "~>1.0")
     gem.add_dependency("sinatra-content-for", "~>0.2.0")
     gem.add_dependency("rack-test",           "~>0.5.0")
@@ -27,7 +26,7 @@ begin
     gem.add_dependency("json_pure",           "~>1.4.0")
     gem.add_dependency("smusher",             "~>0.4.5")
     gem.add_dependency("compass-slickmap",    "~>0.3.0")
-    gem.add_dependency("livereload",          "~>1.4.0")
+    # gem.add_dependency("livereload",          "~>1.4.0")
     
     gem.add_development_dependency("rspec")
     gem.add_development_dependency("cucumber")

lib/middleman/base.rb

@@ -14,7 +14,6 @@ module Middleman
     set :sessions, false
     set :logging, false
     set :environment, ENV['MM_ENV'] || :development
-    set :supported_formats, %w(erb)
     set :index_file, "index.html"
     set :js_dir, "javascripts"
     set :css_dir, "stylesheets"

lib/middleman/builder.rb

@@ -1,9 +1,13 @@
+require 'middleman/base'
 require 'templater'
 require 'middleman/templater+dynamic_renderer.rb'
 
 # Placeholder for any methods the builder needs to abstract to allow feature integration
 module Middleman
   class Builder < ::Templater::Generator
+    
+    @@template_extensions = ::Tilt.mappings.keys << "js"
+    
     # Define source and desintation
     def self.source_root; Dir.pwd; end
     def destination_root; File.join(Dir.pwd, Middleman::Base.build_dir); end
@@ -28,7 +32,8 @@ module Middleman
 
     def self.file(name, *args, &block)
       file_ext = File.extname(args[0])
-      return if Middleman::Base.supported_formats.include? file_ext[1..file_ext.length]
+      
+      return unless ::Tilt[file_ext].nil?
       
       if (args[0] === args[1])
         args[1] = args[0].gsub("#{File.basename(Middleman::Base.views)}/", "").gsub("#{File.basename(Middleman::Base.public)}/", "")
@@ -37,9 +42,8 @@ module Middleman
     end
 
     def self.init!
-      glob! File.basename(Middleman::Base.public), Middleman::Base.supported_formats
-      glob! File.basename(Middleman::Base.views),  %w(sass js)
-      glob! File.basename(Middleman::Base.views),  Middleman::Base.supported_formats - %w(sass js)
+      glob! File.basename(Middleman::Base.public),  @@template_extensions
+      glob! File.basename(Middleman::Base.views),   @@template_extensions
     end
     
     def after_run

lib/middleman/features.rb

@@ -14,25 +14,24 @@ module Middleman
       feature_class = @@features[feature_name]
       feature_class.new(scope) unless feature_class.nil?
     end
-  
+
     def self.all
       @@features
     end
-    
+
   end
 end
 
+# livereload
 %w(asset_host 
    automatic_image_sizes
    cache_buster
    default_helpers
-   livereload
    minify_css
    minify_javascript
    relative_assets
    slickmap
    smush_pngs
-   sprockets
    ugly_haml).each do |feature| 
      
   require File.join("middleman/features", feature)

lib/middleman/features/sprockets.rb

@@ -1,13 +0,0 @@
-class Middleman::Features::Sprockets
-  def initialize(app)
-    require "middleman/features/sprockets/rack"
-    app.use Middleman::Rack::Sprockets, 
-      :root      => Middleman::Base.root, 
-      :load_path => [ File.join("public", Middleman::Base.js_dir),
-                      File.join("views",  Middleman::Base.js_dir) ]
-  end
-end
-
-Middleman::Features.register :sprockets, Middleman::Features::Sprockets, { :auto_enable => true }
-
-                                                

lib/middleman/features/sprockets/rack.rb

@@ -1,64 +0,0 @@
-require 'sprockets'
-
-module Middleman
-  module Rack
-  
-    class Sprockets
-      def initialize(app, options={})
-        @app = app
-        @options = options
-      end
-
-      def call(env)
-        if env["PATH_INFO"].match(/\.js$/)
-          public_file_path = File.join(Middleman::Base.public, env["PATH_INFO"])
-          view_file_path   = File.join(Middleman::Base.views,  env["PATH_INFO"])
-      
-          source_file = ::Rack::File.new(Middleman::Base.public) if File.exists?(public_file_path) 
-          source_file = ::Rack::File.new(Middleman::Base.views)  if File.exists?(view_file_path)
-      
-          if source_file
-            status, headers, response = source_file.call(env)
-            secretary = ::Sprockets::Secretary.new(@options.merge( :source_files => [ response.path ] ))
-            response = secretary.concatenation.to_s
-            headers["Content-Length"] = ::Rack::Utils.bytesize(response).to_s
-            return [status, headers, response]
-          end
-        end
-    
-        @app.call(env)
-      end
-    end
-  end
-end
-
-# Sprockets ruby 1.9 duckpunch
-module Sprockets
-  class SourceFile
-    def source_lines
-      @lines ||= begin
-        lines = []
-
-        comments = []
-        File.open(pathname.absolute_location, 'rb') do |file|
-          file.each do |line|
-            lines << line = SourceLine.new(self, line, file.lineno)
-
-            if line.begins_pdoc_comment? || comments.any?
-              comments << line
-            end
-
-            if line.ends_multiline_comment?
-              if line.ends_pdoc_comment?
-                comments.each { |l| l.comment! }
-              end
-              comments.clear
-            end
-          end
-        end
-
-        lines
-      end
-    end
-  end
-end

spec/builder_spec.rb

@@ -59,8 +59,4 @@ describe "Builder" do
   it "should not build partial files" do
     File.exists?("#{@root_dir}/build/_partial.html").should be_false
   end
-
-  it "should combine javascript" do
-    File.read("#{@root_dir}/build/javascripts/empty-with-include.js").should include("combo")
-  end
 end

spec/fixtures/sample/public/javascripts/to-be-included.js

@@ -1 +0,0 @@
-function() { return "combo"; };

spec/fixtures/sample/views/javascripts/empty-with-include.js

@@ -1 +0,0 @@
-//= require <to-be-included>