Input validation and sanitization in Node.js - Mini Project: Build & Apply

Input Validation and Sanitization in Node.js

📖 Scenario: You are building a simple Node.js server that accepts user input for a username and email. To keep the server safe and clean, you need to check that the input is valid and remove any unwanted characters.

🎯 Goal: Build a Node.js script that validates and sanitizes user input for username and email before using it.

📋 What You'll Learn

Create an object called userInput with keys username and email and exact values.

Add a variable called emailPattern to hold a regular expression for validating emails.

Use a function called sanitizeInput to clean the username by removing spaces and special characters.

Add a final check that uses emailPattern.test() to validate the email and store the result in isEmailValid.

💡 Why This Matters

🌍 Real World

Validating and cleaning user input is essential to prevent errors and security issues in web servers and applications.

💼 Career

Input validation and sanitization are key skills for backend developers, security engineers, and anyone working with user data.

1

Create the initial user input object

Create an object called userInput with these exact entries: username set to " user!name123 " and email set to "[e-mail]".

Node.js

# Create the userInput object with username and email
# Your code here

Need a hint?

Use const userInput = { username: " user!name123 ", email: "[e-mail]" }.

2

Add email validation pattern

Add a variable called emailPattern and assign it a regular expression that matches a simple email format: one or more word characters, an @ symbol, one or more word characters, a dot, and two to four letters.

Node.js

const userInput = {
  username: "  user!name123 ",
  email: "[e-mail]"
};

// Add the emailPattern regular expression below
// Your code here

Need a hint?

Use const emailPattern = /^\w+@\w+\.\w{2,4}$/; to match emails like [e-mail].

3

Sanitize the username input

Write a function called sanitizeInput that takes a string and returns it with all spaces and special characters removed, leaving only letters and numbers. Then create a variable cleanUsername by calling sanitizeInput with userInput.username.

Node.js

const userInput = {
  username: "  user!name123 ",
  email: "[e-mail]"
};

const emailPattern = /^\w+@\w+\.\w{2,4}$/;

// Write sanitizeInput function and create cleanUsername
// Your code here

Need a hint?

Use str.replace(/[^a-zA-Z0-9]/g, '') to remove unwanted characters.

4

Validate the email input

Add a variable called isEmailValid that stores the result of testing userInput.email against emailPattern using emailPattern.test().

Node.js

const userInput = {
  username: "  user!name123 ",
  email: "[e-mail]"
};

const emailPattern = /^\w+@\w+\.\w{2,4}$/;

function sanitizeInput(str) {
  return str.replace(/[^a-zA-Z0-9]/g, '');
}

const cleanUsername = sanitizeInput(userInput.username);

// Add isEmailValid variable using emailPattern.test()
// Your code here

Need a hint?

Use const isEmailValid = emailPattern.test(userInput.email); to check email validity.