class Middleman::CoreExtensions::Data

and makes them available to ‘config.rb`, templates and extensions
The data extension parses YAML and JSON files in the `data/` directory

def after_configuration 

def after_configuration
  return unless @original_data_dir != app.config[:data_dir]
  @watcher.update_path(app.config[:data_dir])
end

def initialize(app, config={}, &block) 

def initialize(app, config={}, &block)
  super
  @data_store = DataStore.new(app, DATA_FILE_MATCHER)
  start_watching(app.config[:data_dir])
end

def start_watching(dir) 

def start_watching(dir)
  @original_data_dir = dir
  # Tell the file watcher to observe the :data_dir
  @watcher = app.files.watch :data,
                             path: File.join(app.root, dir),
                             only: DATA_FILE_MATCHER
  # Setup data files before anything else so they are available when
  # parsing config.rb
  app.files.on_change(:data, &@data_store.method(:update_files))
end