The joy of writing CoffeeScript

build_utils_after.coffee

class BuildUtils
  combine_source_files: (callback) ->
    self = @
    fs.readdir './src', (err, files) ->
      self.error_handler err
      content = new Array()

      files = files.sort()
      for file, index in files when file.indexOf('.') isnt 0 then do (file, index) ->
        fs.readFile "./src/#{file}", 'utf8', (err, fileContent) ->
          self.error_handler err
          content[content.length] = fileContent

          if index is files.length - 1
            callback content

build_utils_before.coffee

class BuildUtils
  combine_source_files: (callback) ->
    self = @
    fs.readdir './src', (err, files) ->
      self.error_handler err
      content = new Array()

      files = files.sort()
      for file, index in files then do (file, index) ->
        unless file.indexOf('.') is 0
          fs.readFile "./src/#{file}", 'utf8', (err, fileContent) ->
            self.error_handler err
            content[content.length] = fileContent

            if index is files.length - 1
              callback content

for_after.coffee

for file, index in files when file.indexOf('.') isnt 0 then do (file, index) ->
  # The code I want to run

for_before.coffee

for file, index in files then do (file, index) ->
  unless file.indexOf('.') is 0
    # The code I want to run