Request validation in Node.js - Mini Project: Build & Apply

Request Validation in Node.js

📖 Scenario: You are building a simple Node.js server that accepts user data through a POST request. To keep your server safe and reliable, you need to check that the data sent by users is correct before using it.

🎯 Goal: Build a Node.js server that validates incoming request data to ensure it has the correct fields and types before processing.

📋 What You'll Learn

Create an object representing user data with specific fields

Add a configuration variable to define required fields

Write a function to validate the user data against the required fields

Integrate the validation function into a simple HTTP server request handler

💡 Why This Matters

🌍 Real World

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

💼 Career

Backend developers often write validation logic to ensure data integrity before processing or storing user data.

1

Create user data object

Create a constant called userData with these exact properties: name set to "Alice", email set to "[e-mail]", and age set to 30.

Node.js

# Create the userData object with name, email, and age
# Your code here

Need a hint?

Use const to create an object with the exact keys and values.

2

Define required fields array

Create a constant called requiredFields that is an array containing the strings "name", "email", and "age".

Node.js

const userData = { name: "Alice", email: "[e-mail]", age: 30 };

# Create the requiredFields array with "name", "email", and "age"
# Your code here

Need a hint?

Use an array literal with the exact strings inside.

3

Write validation function

Write a function called validateUserData that takes one parameter data. Inside, use a for loop with variable field to iterate over requiredFields. For each field, check if data[field] is undefined. If so, return false. After the loop, return true.

Node.js

const userData = { name: "Alice", email: "[e-mail]", age: 30 };
const requiredFields = ["name", "email", "age"];

# Write the validateUserData function below
# Your code here

Need a hint?

Use a for...of loop and check each required field in the data object.

4

Use validation in HTTP server

Create a simple HTTP server using Node.js http module. Inside the request handler, call validateUserData(userData). If it returns true, set response status code to 200 and end with "Valid data". Otherwise, set status code to 400 and end with "Invalid data". Export the server as server.

Node.js

const userData = { name: "Alice", email: "[e-mail]", age: 30 };
const requiredFields = ["name", "email", "age"];

function validateUserData(data) {
    for (const field of requiredFields) {
        if (data[field] === undefined) {
            return false;
        }
    }
    return true;
}

# Create an HTTP server that uses validateUserData and responds accordingly
# Your code here

Need a hint?

Use http.createServer and call validateUserData inside the request handler.