Redis for distributed caching in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Redis client library in Node.js.

Node.js

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

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

Afs

Bexpress

Credis

Dhttp

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'express' or other unrelated modules instead of 'redis'.

Forgetting to install the 'redis' package before requiring it.

We use require('redis') to import the Redis client library in Node.js.

2fill in blank

medium

Complete the code to create a Redis client using the modern Node.js Redis library.

Node.js

const client = redis.[1]();

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

Aconnect

BinitClient

CnewClient

DcreateClient

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'connect' instead of 'createClient'.

Trying to instantiate with 'new redis()' which is not the modern pattern.

The Redis client is created by calling redis.createClient().

3fill in blank

hard

Fix the error in the code to connect the Redis client asynchronously.

Node.js

await client.[1]();

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

Aconnect

Bstart

Copen

Dinit

Attempts:

3 left

💡 Hint

Common Mistakes

Using synchronous connect methods that do not exist.

Forgetting to await the connection.

The Redis client connects asynchronously using await client.connect().

4fill in blank

hard

Fill both blanks to set a key with a value and an expiration time in Redis.

Node.js

await client.set('[1]', '[2]', { EX: 60 });

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

AuserToken

BsessionId

C12345

Dabcdef

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up key and value positions.

Using numeric values as keys.

We set the key 'sessionId' with the value 'abcdef' and expiration of 60 seconds.

5fill in blank

hard

Fill all three blanks to get a cached value, check if it exists, and log it or a fallback message.

Node.js

const cached = await client.[1]('[2]');
if (cached [3] null) {
  console.log('Cached value:', cached);
} else {
  console.log('No cached value found');
}

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

Aget

BuserToken

C!==

D===

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '!==', causing wrong condition.

Using wrong method like 'fetch' instead of 'get'.

We use client.get('userToken') to get the cached value, then check if it is not equal to null with !==.