Combine & Minimize JavaScript using Ruby

AC shared with me this great way of combining many .js files to one big file. I am not sure if all the code was his or if some he found, so credit to whoever helped out with this. This is really a great and easy way to do this, and you can run this on a postscript or even from NAnt if you wanted. In order to use it, you will first need to download and install some software:

1. Java
2. Ruby (http://rubyinstaller.rubyforge.org/wiki/wiki.pl)
3. RubyGems (http://rubyforge.org/frs/?group_id=126 & unzip to lcoation)
4. command line > gem install rake
5. command line > gem install rio

For those that want to know how to install Gems:

• command line > ruby.exe c:\rubygems-1.3.1\setup.rb

Finally, make sure you have E:\Ruby\bin; (change E: to your drive) as a path variable as it makes things easier.

For the code below, I need to download jslint.js, jsmin.js, pack.js, and packer.js and store them in the same folder as well.

You then have a batch file with has just one word: rake. You run this batch file (which is in the same directory as your rake file explained below)

Now, the code is all in one little Rakefile:

require 'rio'

$rhino_compile_enabled = false
$minify_enabled = true
$jslint_enabled = false
$output_dir = "out"

puts "Starting..."

def get_files
  files = []

   files << as_is("http://yui.yahooapis.com/combo?2.5.2/build/yahoo-dom-event/yahoo-dom-event.js")
   files << as_is("http://yui.yahooapis.com/combo?2.5.2/build/yahoo-dom-event/yahoo-dom-event.js&2.5.2/build/container/container-min.js&2.5.2/build/cookie/cookie-beta-min.js&2.5.2/build/json/json-min.js&2.5.2/build/element/element-beta-min.js&2.5.2/build/datasource/datasource-beta-min.js&2.5.2/build/connection/connection-min.js&2.5.2/build/charts/charts-experimental-min.js")

   files << minify("../WebApp/js/diag.js")
   files << as_is("../WebApp/js/jquery-1.3.1.min.js")
   #add more files here

  end

def as_is(file_path)

 task file_path do
 end

 file_path
end

def minify(file_path)
 mkdir_if_not_exist "#{$output_dir}/min" 
 min_path = get_min_path(file_path)

 file min_path => file_path do
   do_jslint file_path
   do_minify file_path, min_path
 end

 min_path
end

def do_minify(file_path, min_path)
 if $minify_enabled
   `java -cp build/js.jar  org.mozilla.javascript.tools.shell.Main  build/min.js #{file_path} #{min_path}`
 else
   rio(min_path) < rio(file_path)
 end
end

def do_jslint(file_path)
 return unless $jslint_enabled

 puts "jslint #{file_path}"

 mkdir_if_not_exist "#{$output_dir}/tmp"
 mkdir_if_not_exist "#{$output_dir}/jslint_errors"
 tmp = "#{$output_dir}/tmp/jslint.tmp.js"

 rio(tmp) < rio('jslint-options.js')
 rio(tmp) << rio(file_path)

 errors = `java -cp build/js.jar org.mozilla.javascript.tools.shell.Main build/jslint.js #{tmp}`
  
 unless /jslint: No problems found/.match(errors)
   rio("#{$output_dir}/jslint_errors/#{File.basename(file_path)}.err") < errors
 end
end

def get_min_path(file_path)
  "#{$output_dir}/min/" + File.basename(file_path) + ".min"
end

def mkdir_if_not_exist(dir_name)
 Dir.mkdir dir_name unless File.exist? dir_name
end

def do_rhino_compile(file_path)
 return unless $rhino_compile_enabled

 puts "Rhino compiling..."
 `java -cp build/js.jar org.mozilla.javascript.tools.jsc.Main #{file_path}`
 puts "Rhino compilation done."
end

def  get_combined_path
 "#{$output_dir}/combined.js"
end

task :combine => get_files do
 mkdir_if_not_exist "#{$output_dir}"
 combined = get_combined_path

 rio(combined) < "
/*
* Combined JavaScript.
*     #{Time.now}
*/
"

 get_files.each do |file_path|

   puts "Combining: #{file_path}"
   rio(combined) << "

/************************************************************************
* Source: #{file_path}
************************************************************************/

"
   rio(combined) << rio(file_path)

   puts 'next...'
 end
end

task :rhino_compile do
 do_rhino_compile get_combined_path
end

task :copy_combined do
 rio("../WebApp/Combined/combined.js") < rio(get_combined_path)
end

task :default => [:combine, :copy_combined]

Thanks AC for this.