path.join for cross-platform paths in Node.js - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Node.js code using path.join?

Consider the following code snippet using path.join on a Windows system. What will be the output printed?

Node.js

import path from 'path';
console.log(path.join('folder', 'subfolder', 'file.txt'));

A 'folder\\subfolder\\file.txt'

B 'folder/subfolder/file.txt'

C 'folder\\subfolder/file.txt'

D 'folder/subfolder\\file.txt'

💡 Hint

Remember that path.join uses the platform-specific separator.

On Windows, path.join uses backslashes \\ as separators. So the output joins the parts with \\.

❓ Predict Output

intermediate

What does path.join output on POSIX (Linux/macOS)?

Given this code running on a POSIX system, what is the output?

Node.js

import path from 'path';
console.log(path.join('/usr', 'local', 'bin'));

A '/usr/local/bin'

B '/usr\\local\\bin'

C '/usr/local\\bin'

D 'usr/local/bin'

💡 Hint

POSIX systems use forward slashes as path separators.

On POSIX systems, path.join uses forward slashes / to join paths.

❓ component_behavior

advanced

How does path.join handle absolute paths in arguments?

What will be the output of this code snippet?

Node.js

import path from 'path';
console.log(path.join('folder', '/absolute', 'file.txt'));

A 'folder\\absolute\\file.txt'

B 'folder\\/absolute\\file.txt'

C 'folder/absolute/file.txt'

D '/absolute/file.txt'

💡 Hint

An absolute path in any argument resets the path from that point.

When path.join encounters an absolute path, it discards all previous segments and starts from the absolute path.

📝 Syntax

advanced

Which option correctly imports and uses path.join in ES modules?

Select the correct code snippet that imports path and uses path.join to join 'a' and 'b'.

A

const path = require('path');
console.log(path.join('a', 'b'));

B

import * as path from 'path';
console.log(path.join('a', 'b'));

C

import path from 'path';
console.log(path.join('a', 'b'));

D

import { join } from 'path';
console.log(join('a', 'b'));

💡 Hint

ES modules use import syntax, not require.

In ES modules, import * as path from 'path' is the correct way to import the entire module. Option B uses CommonJS require which is invalid in ES modules. Option B imports the default export, but Node.js 'path' module does not have a default export. Option B imports only join which is valid if you want to use join directly.

🔧 Debug

expert

Why does this path.join code throw an error?

Examine the code below. Why does it throw a TypeError?

Node.js

import path from 'path';
const parts = null;
console.log(path.join(...parts));

A 'parts' is an empty array, so output is an empty string.

B 'path' module is not imported correctly.

C 'parts' is null and cannot be spread, causing a TypeError.

D 'path.join' does not accept spread arguments.

💡 Hint

Check the value and type of 'parts' before spreading.

Spreading a null value causes a TypeError because null is not iterable. The error is not related to path.join or import.