How to Use path.basename in Node.js: Simple Guide

In Node.js, use path.basename(path, ext) to get the last part of a file path, usually the file name. The optional ext argument removes a file extension if it matches. This method helps extract file names from full paths easily.

Syntax

The path.basename method takes two arguments:

• path: A string representing the full file path.
• ext (optional): A string for the file extension to remove from the result.

It returns the last portion of the path, typically the file name.

javascript

const path = require('path');

path.basename(pathString[, ext])

Example

This example shows how to get the file name from a full path and how to remove the extension if needed.

javascript

const path = require('path');

const fullPath = '/home/user/docs/letter.txt';

// Get file name with extension
const fileName = path.basename(fullPath);
console.log(fileName); // Outputs: letter.txt

// Get file name without extension
const fileNameNoExt = path.basename(fullPath, '.txt');
console.log(fileNameNoExt); // Outputs: letter

Output

letter.txt
letter

Common Pitfalls

Common mistakes include:

• Not importing the path module before using basename.
• Passing a wrong or empty path string, which returns an empty string.
• Using the ext argument incorrectly, such as omitting the dot . in the extension.

Always ensure the extension string starts with a dot when using the second argument.

javascript

const path = require('path');

// Wrong: missing dot in extension
const wrongExt = path.basename('/file/example.txt', 'txt');
console.log(wrongExt); // Outputs: example.txt (extension not removed)

// Correct: include dot
const correctExt = path.basename('/file/example.txt', '.txt');
console.log(correctExt); // Outputs: example

Output

example.txt
example

Quick Reference

Parameter	Description	Example
path	Full file path string	'/folder/file.txt'
ext (optional)	Extension to remove (include dot)	'.txt'
Return	Last part of path, file name	'file.txt' or 'file' if ext removed

Key Takeaways

Use path.basename(path) to get the file name from a full path string.

Pass the file extension with a leading dot as the second argument to remove it.

Always import the path module before using path.basename.

If the extension argument is incorrect or missing the dot, it won't remove the extension.

An empty or invalid path returns an empty string.