Node.js File Paths

Every file in the system has a path. On Linux and macOS, a path might look like: /users/joe/file.txt while Windows computers are different, and have a structure such as: C:\users\joe\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: gets the parent folder of a file
  • basename: gets the filename part
  • extname: gets the file extension

Example

const notes = '/users/joe/notes.txt';

path.dirname(notes); // /users/joe
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 = 'joe';
path.join('/', 'users', name, 'notes.txt'); // '/users/joe/notes.txt'

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

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

In this case Node.js will simply append /joe.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', 'joe.txt'); // '/Users/joe/tmp/joe.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', 'joe.txt'); // '/etc/joe.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/joe/..//test.txt'); // '/users/test.txt'

Neither resolve nor normalize will check if the path exists. They just calculate a path based on the information they got.