unchain_vars.rb

# Converts global chained `var`s into single-line vars.
#
# Example:
#
# >> cat app/assets/javascripts/test.js
# var A = require('a'),
#     B = require('b'),
#     C = B.C;
#
# var D = function() {};
#
# >> ruby unchain_vars.rb app/assets/javascripts/**/*.js
#
# >> cat app/assets/javascripts/test.js
# var A = require('a');
# var B = require('b');
# var C = B.C;
#
# var D = function() {};
#
filenames = ARGV

filenames.each do |filename|
  active = false
  result = ''
  File.open(filename).each do |line|
    if line =~ /^var .*,$/
      active = true
    end

    if active
      result << line.gsub(/^(var | +)(.+)[,;]$/, 'var \2;')
    else
      result << line
    end

    if active && line =~ /;$/
      active = false
    end
  end
  File.write(filename, result)
end