rename.rb

#!/usr/bin/env ruby

ROOT_PATH = File.dirname(__FILE__) + '/js/dashboard/'
COMPONENT_REGEX = /window\.(\w+) =.+(React|Reflux)/
files = Dir.glob(ROOT_PATH + "**/*.{js,jsx,coffee,cjsx}")
# hard coded modules that we want to require. This list will be amended by searching for
# `window.X = (React|Redux)` definitions in the code base
components = [
  {name: 'UserActions', import_path: 'user_actions'},
  {name: 'UrlService', import_path: 'services/url_service'},
  {name: 'Reflux', import_path: 'reflux'},
  {name: 'PureRenderMixin', import_path: 'react-addons-pure-render-mixin'},
  {name: 'ReactDOM', import_path: 'react-dom'},
  {name: 'React', import_path: 'react'},
  {name: 'classNames', import_path: 'classnames'},
  {name: 'InlineSVG', import_path: 'react-inline-svg'},
  {name: 'Routes', import_path: 'routes'},
  {name: 'HotKeyMixin', import_path: 'mixins/hot_key_mixin'},
  {name: 'Analytics', import_path: 'lib/analytics'},
  {name: 'Timezone', import_path: 'lib/timezone'},
  {name: 'Update', import_path: 'lib/update'},
  {name: 'APIRequestMixin', import_path: 'mixins/api_request_mixin'},
  {name: 'DocumentEventListenerMixin', import_path: 'mixins/document_event_listener_mixin'},
  {name: 'Utils', import_path: 'lib/utils'},
]

def make_import_path(full_path)
  full_path.gsub(ROOT_PATH, "").gsub(/\.\w+$/, '')
end

def make_import_statement(name, file_name, component_path)
  path = make_import_path(component_path)
  if is_coffee?(file_name)
    "#{name} = require('#{path}')"
  else
    "import #{name} from '#{path}';"
  end
end

def is_coffee?(file_name)
  file_name.match(/\.(coffee|cjsx)/)
end

# for a files contents, finds the place where we should add the next import statment.
# this should be at the top, but after any comment blocks or other require/import statments already
# in the file.
def find_insertion_point(contents, file_name)
  if is_coffee?(file_name)
    comment = /^\#/
    block_comment_start = /\#{3}/
    block_comment_end = /\#{3}/
    import = /require/
  else
    comment = /^\/\//
    block_comment_start = /\/\*/
    block_comment_end = /\*\//
    import = /(import|require)/
  end

  line_number = 0
  in_block_comment = false
  lines = contents.split("\n")
  # step through the lines of the file until we reach the first line that isn't a comment or a
  # a require statement.
  lines.each_with_index do |line, index|
    if in_block_comment
      if line.match(block_comment_end)
        in_block_comment = false
      end
      line_number = line_number + 1
      next
    end
    if line.match(block_comment_start)
      in_block_comment = true
      line_number = line_number + 1
      next
    end

    if line.match(comment) || line.match(import)
      line_number = line_number + 1
    elsif line.empty? && lines[index + 1].match(import)
      line_number = line_number + 1
    else
      break
    end
  end
  return line_number
end

# iterate over all files and find "window.Foo =" statements
# replace those with explicit exports and add them to the list of components
files.each do |file_name|
  text = File.read(file_name)
  matches = text.scan(COMPONENT_REGEX)
  components += matches.map do |match|
    {name: match[0], import_path: file_name}
  end

  replacement =
    if is_coffee?(file_name)
      'module.exports = \2'
    else
      'export default \2'
    end

  new_contents = text.gsub(COMPONENT_REGEX, replacement)

  # To write changes to the file, use:
  File.open(file_name, "w") {|file| file.puts new_contents }
end

# Add import/require statements to all the files where global components have been used
files.each do |file_name|
  text = File.read(file_name)
  new_contents = text

  components.each do |component|
    # skip if we are in the component file itself
    next if make_import_path(file_name) == component[:import_path]
    name = component[:name]
    # skip if component isn't used in this file
    next unless text.match(/(\W#{name}\W|^#{name}|#{name}\.)/)
    # skip if we already imported that component
    next if new_contents.match(/^(import #{name}|#{name} = require)/)
    # find the next insertion point for an import statement
    insertion_point = find_insertion_point(new_contents, file_name)
    # split into lines
    lines = new_contents.split("\n")
    if insertion_point == 0
      lines.insert(insertion_point, "")
    end
    # insert new line
    lines.insert(insertion_point, make_import_statement(name, file_name, component[:import_path]))
    # join everything again
    new_contents = lines.join("\n")
  end

  # write the new contents
  File.open(file_name, "w") {|file| file.puts new_contents }
end