packr_compress_to_file.rb

require 'rubygems'
require 'packr'

class Packr
  
  def self.compress_to_file(filename, options = {})
    defaults = {
      :target_file => filename.gsub(/\.js$/, '.min.js'),
      :shrink_vars => true
    }
    options = defaults.merge options
    
    code = File.read(filename)
    compressed = Packr.pack(code, options)
    File.open(options[:target_file], 'wb') { |f| f.write(compressed) }
  end
end