How I converted all javascript files in a codebase from amd imports to commonjs

.vimrc

function! ReplaceRequireJS()
  StripTrailingWhitespaces
  normal gg
  call search(')')
  let @e= line('.')
  call MaybeAddNewLineBelow()
  call PrependModuleExports()
  normal gg
  normal @eJ
  normal ^"aD
  exe 'read !ruby replace_requirejs.rb "' . @a . '"'
  normal j<G
  normal ggdd
endfunction

function! MaybeAddNewLineBelow()
  normal j
  if len(getline(line('.'))) != 0
    normal O
  endif
endfunction

function! PrependModuleExports()
  normal G
  call search('\v^\s{2}\w+', 'b')
  if getline('.')[col('.')-1] == '}'
    " note that ^ and 0 are switched in my dotfiles!
    normal %^
  endif
  normal xi module.exports =
endfunction

nnoremap ,jj :call ReplaceRequireJS()<CR>

replace_requirejs.rb

REGEX = /\[(.*?)\].*?\((.*?)\)/

def match_path_string_and_name_string(string)
  _, path_string, name_string = REGEX.match(string).to_a
  raise(
    "matched '#{path_string}' and '#{name_string}' from '#{string}'"
  ) unless path_string && name_string
  [path_string, name_string]
end

def strip(string)
  string.gsub(',', '').gsub('"', '').gsub("'", '')
end

def paths_zipped_with_names(path_string, name_string)
  strip(path_string).split.zip(
    strip(name_string).split
  )
end

def import_lines_from(path_name_pairs)
  counter = 0
  path_name_pairs.map do |path, name|
    name ||= "UnusedModule#{counter += 1}"
    "#{name} = require('#{path}')"
  end
end

if __FILE__ == $0
  path_string, name_string = match_path_string_and_name_string(ARGV[0])
  paths_zipped_with_names = paths_zipped_with_names(path_string, name_string)
  import_lines_from(paths_zipped_with_names).each do |import_line|
    puts import_line
  end
end