path.extname for file extensions in Node.js - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of path.extname for a simple file?

Given the following Node.js code using path.extname, what will be printed to the console?

Node.js

import path from 'path';
console.log(path.extname('photo.jpg'));

A '.jpg'

B '.photo'

C 'photo.jpg'

D ''

💡 Hint

Remember, path.extname returns the extension including the dot.

The path.extname function returns the file extension including the dot. For 'photo.jpg', it returns '.jpg'.

❓ Predict Output

intermediate

What does path.extname return for a file with multiple dots?

What will be the output of this code snippet?

Node.js

import path from 'path';
console.log(path.extname('archive.tar.gz'));

A ''

B '.tar.gz'

C '.tar'

D '.gz'

💡 Hint

The extension is the substring after the last dot.

path.extname returns the substring from the last dot to the end. For 'archive.tar.gz', it returns '.gz'.

❓ Predict Output

advanced

What is the output of path.extname for a hidden file?

Consider this code. What will it print?

Node.js

import path from 'path';
console.log(path.extname('.env'));

A ''

B '.'

C '.env.'

D '.env'

💡 Hint

Hidden files start with a dot but may not have an extension.

Files like '.env' start with a dot but have no extension after that. path.extname returns an empty string.

❓ Predict Output

advanced

What does path.extname return for a directory path ending with a dot?

What will this code output?

Node.js

import path from 'path';
console.log(path.extname('/folder.name/.hiddenfile'));

A '.hiddenfile'

B ''

C '.name'

D '.file'

💡 Hint

The extension is based on the last part of the path, not directories.

The last part is '.hiddenfile' which starts with a dot but has no extension after it, so path.extname returns an empty string.

❓ Predict Output

expert

What is the output of path.extname for a filename with trailing dot?

Analyze this code and choose the correct output:

Node.js

import path from 'path';
console.log(path.extname('filename.'));

A '.filename'

B ''

C '.'

D 'filename.'

💡 Hint

The extension includes the last dot and characters after it, even if empty.

When the filename ends with a dot, path.extname returns the dot as the extension.