path.basename and path.dirname in Node.js - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of path.basename with extension

What is the output of the following Node.js code using path.basename?

Node.js

import path from 'path';
const filePath = '/home/user/docs/letter.txt';
console.log(path.basename(filePath, '.txt'));

A 'letter'

B '/home/user/docs/letter.txt'

C 'docs'

D 'letter.txt'

💡 Hint

The second argument to path.basename removes the file extension if it matches.

The path.basename function returns the last part of a path. When you provide a second argument, it removes that extension from the result if it matches. Here, '.txt' is removed from 'letter.txt', so the output is 'letter'.

❓ Predict Output

intermediate

Output of path.dirname with nested path

What does the following code print using path.dirname?

Node.js

import path from 'path';
const filePath = '/var/www/html/index.html';
console.log(path.dirname(filePath));

A '/var/www/html/index.html'

B 'html'

C '/var/www'

D '/var/www/html'

💡 Hint

path.dirname returns the directory part of the path, excluding the file name.

The path.dirname function returns everything before the last slash in the path. Here, it returns '/var/www/html' because 'index.html' is the file name.

❓ component_behavior

advanced

Behavior of path.basename with trailing slash

What is the output of this code snippet using path.basename on a path with a trailing slash?

Node.js

import path from 'path';
const dirPath = '/usr/local/bin/';
console.log(path.basename(dirPath));

A 'bin'

B 'local'

C '' (empty string)

D '/'

💡 Hint

path.basename returns an empty string when the path ends with a trailing slash.

The path.basename function returns the last portion of a path, ignoring trailing slashes. Here, '/usr/local/bin/' ends with a slash, but path.basename ignores it and returns 'bin'.

📝 Syntax

advanced

Identify the syntax error in path usage

Which option contains a syntax error when importing and using path.dirname in Node.js ES modules?

A import path from 'path'; console.log(path.dirname('/a/b/c.txt'));

B const path = require('path'); console.log(path.dirname('/a/b/c.txt'));

C import path from 'path'; console.log(path.dirname('/a/b/c.txt')

D import { dirname } from 'path'; console.log(dirname('/a/b/c.txt'));

💡 Hint

Check for missing parentheses or syntax mistakes in the code.

Option C is missing a closing parenthesis in the console.log call, causing a syntax error.

🔧 Debug

expert

Why does path.basename return an empty string?

Given the code below, why does path.basename return an empty string?

Node.js

import path from 'path';
const p = '/folder/subfolder/';
console.log(path.basename(p));

A Because the path is invalid and basename throws an error.

B Because the path ends with a slash, so basename returns empty string.

C Because basename always returns empty string for directories.

D Because the path is relative, basename returns empty string.

💡 Hint

Think about how trailing slashes affect basename output.

path.basename returns an empty string if the path ends with a slash (/), treating it as a directory path with no trailing filename. Here, '/folder/subfolder/' ends with a slash, so it returns an empty string.