Sanitization methods in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to sanitize the input by trimming whitespace.

Express

const sanitizedInput = req.body.username.[1]();

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

Anormalize

Bescape

CtoLowerCase

Dtrim

Attempts:

3 left

💡 Hint

Common Mistakes

Using escape() instead of trim() removes HTML characters, not spaces.

normalize() changes Unicode forms, not whitespace.

toLowerCase() changes case, not whitespace.

The trim() method removes whitespace from both ends of a string, which is a basic sanitization step.

2fill in blank

medium

Complete the code to escape HTML characters in the input.

Express

const safeInput = req.body.comment.[1]();

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

Aescape

Btrim

CtoUpperCase

Dslice

Attempts:

3 left

💡 Hint

Common Mistakes

Using trim() only removes spaces, not HTML characters.

toUpperCase() changes letter case, not safety.

slice() extracts parts of strings, no sanitization.

The escape() method converts HTML characters to safe entities, preventing injection attacks.

3fill in blank

hard

Fix the error in the sanitization chain to properly normalize and trim the input.

Express

const cleanInput = req.body.email.[1]().trim();

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

AtoLowerCase

Bescape

Cnormalize

Dslice

Attempts:

3 left

💡 Hint

Common Mistakes

Using escape() does not normalize Unicode.

toLowerCase() changes case but not normalization.

slice() does not sanitize or normalize.

The normalize() method standardizes Unicode characters, which is important before trimming.

4fill in blank

hard

Fill both blanks to sanitize input by trimming and escaping.

Express

const safeText = req.body.text.[1]().[2]();

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

Atrim

Bescape

CtoLowerCase

Dnormalize

Attempts:

3 left

💡 Hint

Common Mistakes

Reversing the order can cause issues.

Using toLowerCase does not sanitize input.

Normalize is not needed here.

First trim removes spaces, then escape converts HTML characters to safe entities.

5fill in blank

hard

Fill all three blanks to sanitize input by normalizing, trimming, and escaping.

Express

const finalInput = req.body.input.[1]().[2]().[3]();

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

Anormalize

Btrim

Cescape

DtoLowerCase

Attempts:

3 left

💡 Hint

Common Mistakes

Changing order can cause incorrect sanitization.

Using toLowerCase does not sanitize input.

Skipping normalization can cause Unicode issues.

Normalize Unicode first, then trim spaces, and finally escape HTML characters for safety.