Node.js File Paths

System 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 have a different 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.

Using the path Module

You include this module in your files using:

const path = require('node: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

CJS

const path = require('node:path')
const notes = '/users/joe/notes.txt'

path.dirname(notes) // /users/joe
path.extname(notes) // .txt

MJS

import path from 'node:path'
const notes = '/users/joe/notes.txt'

path.dirname(notes) // /users/joe
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():

path.join('/users', 'joe', 'file.txt') // /users/joe/file.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
path.resolve('tmp', 'joe.txt') // /Users/joe/tmp/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 as a folder, resolve will use the first as a base for the second.

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.