File paths

How to interact with file paths and manipulate them in Node

Every file in the system has a path.

On Linux and macOS, a path might look like:

/users/flavio/file.txt

while Windows computers are different, and have a structure such as:

C:\users\flavio\file.txt

You need to pay attention when using paths in your applications, as this difference must be taken into account.

You include this module in your files using

const path = require('path')

and you can start using its methods.

Getting information out of a path

Given a path, you can extract information out of it using those methods:

  • dirname: get the parent folder of a file
  • basename: get the filename part
  • extname: get the file extension

Example:

const notes = '/users/flavio/notes.txt'

path.dirname(notes) // /users/flavio
path.basename(notes) // notes.txt
path.extname(notes) // .txt

You can get the file name without the extension by specifying a second argument to basename:

path.basename(notes, path.extname(notes)) //notes

Working with paths

You can join two or more parts of a path by using path.join():

const name = 'flavio'
path.join('/', 'users', name, 'notes.txt') //'/users/flavio/notes.txt'

You can get the absolute path calculation of a relative path using path.resolve():

path.resolve('flavio.txt') //'/Users/flavio/flavio.txt' if run from my home folder

In this case Node will simply append /flavio.txt to the current working directory. If you specify a second parameter folder, resolve will use the first as a base for the second:

path.resolve('tmp', 'flavio.txt')//'/Users/flavio/tmp/flavio.txt' if run from my home folder

If the first parameter starts with a slash, that means it's an absolute path:

path.resolve('/etc', 'flavio.txt')//'/etc/flavio.txt'

path.normalize() is another useful function, that will try and calculate the actual path, when it contains relative specifiers like . or .., or double slashes:

path.normalize('/users/flavio/..//test.txt') ///users/test.txt

Both resolve and normalize will not check if the path exists. They just calculate a path based on the information they got.






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