Input validation and sanitization in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Express framework.

Node.js

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

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Aexpress

Bhttp

Cfs

Dpath

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'http' instead of 'express' to import the framework.

The Express framework is imported by requiring 'express'.

2fill in blank

medium

Complete the code to use the express.json() middleware for parsing JSON input.

Node.js

app.use([1]());

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AcookieParser

Bexpress.json

CbodyParser.text

Dexpress.urlencoded

Attempts:

3 left

💡 Hint

Common Mistakes

Using express.urlencoded() which parses URL-encoded data instead of JSON.

express.json() middleware parses incoming JSON requests.

3fill in blank

hard

Fix the error in the validation code to check if the input 'age' is a number.

Node.js

if (typeof [1] !== 'number') {
  res.status(400).send('Age must be a number');
}

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Areq.body.age

Breq.params.age

Creq.query.age

Dreq.age

Attempts:

3 left

💡 Hint

Common Mistakes

Using req.params.age or req.query.age when input is sent in JSON body.

Input data from JSON body is accessed via req.body.age.

4fill in blank

hard

Fill both blanks to sanitize and validate a username input using the 'validator' library.

Node.js

const sanitizedUsername = validator.[1](req.body.username);
if (!validator.[2](sanitizedUsername)) {
  res.status(400).send('Invalid username');
}

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Aescape

BisEmail

CisAlphanumeric

Dtrim

Attempts:

3 left

💡 Hint

Common Mistakes

Using isEmail() to validate username which is incorrect.

Use escape() to sanitize input and isAlphanumeric() to validate username characters.

5fill in blank

hard

Fill all three blanks to create a middleware that validates and sanitizes an email input.

Node.js

function validateEmail(req, res, next) {
  const email = validator.[1](req.body.email);
  if (!validator.[2](email)) {
    return res.status(400).send('Invalid email');
  }
  req.body.email = email[3]();
  next();
}

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AnormalizeEmail

BisEmail

Ctrim

Descape

Attempts:

3 left

💡 Hint

Common Mistakes

Using escape() on email which can break the format.

normalizeEmail() cleans the email, isEmail() validates it, and trim() removes extra spaces.