JWT token creation in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the JWT library.

Express

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

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

Ajsonwebtoken

Bexpress

Cbody-parser

Dcors

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'express' instead of 'jsonwebtoken' for JWT handling.

Forgetting to install the 'jsonwebtoken' package.

The jsonwebtoken package is used to create and verify JWT tokens in Express.

2fill in blank

medium

Complete the code to create a JWT token with a payload.

Express

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

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

Aexpress

Bmysecretkey

C12345

Dtoken

Attempts:

3 left

💡 Hint

Common Mistakes

Using a public or guessable string as the secret.

Passing the payload as the secret key.

The second argument to jwt.sign is the secret key used to sign the token.

3fill in blank

hard

Fix the error in the code to set token expiration to 1 hour.

Express

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

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

Atimeout

Bexpire

Cduration

DexpiresIn

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'expire' or 'timeout' instead of 'expiresIn'.

Passing expiration as part of the payload instead of options.

The correct option to set token expiration is expiresIn.

4fill in blank

hard

Fill both blanks to verify a JWT token and extract the payload.

Express

jwt.[1](token, 'mysecretkey', (err, [2]) => {
  if (err) {
    console.error('Invalid token');
  } else {
    console.log([2]);
  }
});

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

Averify

Bdecode

Cpayload

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'decode' instead of 'verify' to check token validity.

Naming the decoded payload as 'payload' instead of 'data' (both work but only one is correct here).

Use jwt.verify to check the token and the callback receives the decoded data, often named data.

5fill in blank

hard

Fill all three blanks to create a JWT token with user info, secret, and expiration.

Express

const token = jwt.sign({ [1]: 'alice' }, '[2]', { [3]: '2h' });

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

Ausername

Bsupersecret

CexpiresIn

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'user' instead of 'username' as payload key.

Using wrong option name for expiration.

Using a weak or empty secret.

The payload key is 'username', the secret is 'supersecret', and the expiration option is 'expiresIn'.