JWT token generation and verification in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the JWT library.

Node.js

const jwt = require('[1]');

Drag options to blanks, or click blank then click option'

Ajsonwebtoken

Bexpress

Chttp

Dcrypto

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'express' instead of 'jsonwebtoken'.

Using 'crypto' which is for cryptography but not JWT.

The jsonwebtoken package is used to generate and verify JWT tokens in Node.js.

2fill in blank

medium

Complete the code to generate a JWT token with a secret key.

Node.js

const token = jwt.sign({ userId: 123 }, '[1]');

Drag options to blanks, or click blank then click option'

A12345

BtokenSecret

CmySecretKey

DjwtKey

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number instead of a string as the secret key.

Leaving the secret key empty.

The secret key is a string used to sign the token securely. Here, 'mySecretKey' is used as an example.

3fill in blank

hard

Fix the error in the code to verify a JWT token using the secret key.

Node.js

const decoded = jwt.verify(token, '[1]');

Drag options to blanks, or click blank then click option'

Ajwt

Btoken

Csecret

DmySecretKey

Attempts:

3 left

💡 Hint

Common Mistakes

Using the token itself as the secret key.

Using a different or undefined secret key.

The jwt.verify function requires the same secret key used to sign the token to decode it correctly.

4fill in blank

hard

Fill both blanks to generate a token with an expiration time of 1 hour.

Node.js

const token = jwt.sign({ id: user.id }, '[1]', { expiresIn: '[2]' });

Drag options to blanks, or click blank then click option'

AmySecretKey

B2h

C1h

D3600

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong expiration format like '2h' or a number without quotes.

Forgetting to add the expiresIn option.

The secret key is needed to sign the token, and the expiresIn option sets the token to expire in 1 hour using '1h'.

5fill in blank

hard

Fill all three blanks to decode a token safely with error handling.

Node.js

try {
  const decoded = jwt.[1](token, '[2]');
  console.log(decoded.[3]);
} catch (err) {
  console.error('Invalid token');
}

Drag options to blanks, or click blank then click option'

Averify

BmySecretKey

CuserId

Dsign

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'sign' instead of 'verify' to decode.

Using a wrong secret key.

Accessing a wrong property from decoded token.

Use verify to decode the token with the secret key 'mySecretKey'. Then access the userId property from the decoded token.