title: Hash of folders in nodejs
body: <p>In my project, I want to calculate hash of folders.
  For example, there are 10 folders and these folders have many sub files. I know many way to get hash of files but is there any way for get hash of every folder?</p>
  <p>My purpose in doing this is to understand if the files in the folder have changed.</p>
  <p>I am open to suggestions and different ideas, I need your help. Thanks in advance.</p>