Important Core Modules

• path
  • path.normalize
  • path.join
  • path.dirname, path. basename, path.extname
• fs (file-system)
• os (operating-system)
• util (general utilities)
  • util.inherits
  • util.log
  • util.isArray
  • util.isDate
  • util.isError
• require (function)
• events
• stream
  • stream.Readable
  • stream.Writebale
  • stream.Duplex
  • stream.Transform
  • NOTE! all the above inherit from Stream which you should not use directly.
  • NOTE! Stream inherits from EventEmitter

Requiring a module steps made by node

Then the follow is the logic followed by Node.js for a require('something') statement:

• If something is a core module, return it.
• If something is a relative path (starts with ‘./’ , ‘../’) return that file OR folder.
• If not, look for node_modules/filename or node_modules/foldername each level up until you
find a file OR folder that matches something.

When matching a file OR folder:, follow these steps:
• If it matched a file name, return it.
• If it matched a folder name and it has package.json with main, return that file.
• If it matched a folder name and it has an index file, return it.