Node File Paths

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 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.

My advice is to use path.join() when you build paths from parts, and path.resolve() when you need an absolute path from the current working directory.