juicy_script.rb

require "juicer"
require "juicer/merger/javascript_merger"
require "juicer/minifyer/yui_compressor"
require "pathname"

class JuicyScript
  def initialize(script)
    @script = script
  end

  def merged(force = false)
    merger = Juicer::Merger::JavaScriptMerger.new(path)
    output = StringIO.new
    merger.save(output)

    output(output.rewind && output.read, merger.files)
  end

  def minified(force = false)
    script = path("min.js")
    File.delete(script) if force && File.exists?(script)
    `juicer merge -s -o #{script} #{path}` if !File.exists?(script)
    output(File.read(script))
  end

  def path(suffix = "js")
    script = @script.sub(/((\.min)?\.js)?$/, ".#{suffix}")
    script = script !~ /^lib/ ? "src/#{script}" : script
    File.join(self.class.root, script)
  end

  def relative_path(script = path)
    script = script.sub("#{self.class.root}/", "")
  end

  def output(contents, dependencies = nil)
    dependencies ||= Juicer::JavaScriptDependencyResolver.new.resolve(path)
    dependencies = dependencies.collect { |f| self.relative_path(f) }

    <<-JS
/**
 * #{relative_path} as packaged by Juicer
 *
 * #{dependencies.join("\n * ")}
 *
 * Total: #{contents.length / 1024.0} kbytes
 */

#{contents}
    JS
  end

  def self.root
    @@root ||= File.join(Rails.root, "public/design/js")
  end

  def self.compressor
    return @@compressor if @@compressor
    juicer_home = File.join(Juicer.home, "lib/yui_compressor/bin")
    @@compressor = Juicer::Minifyer::YuiCompressor.new({ :bin_path => juicer_home })
  end
end