Why objects are needed in Javascript - See It in Action

Why Objects Are Needed in JavaScript

📖 Scenario: Imagine you run a small bookstore. You want to keep track of books with their title, author, and price. Using separate variables for each book detail is confusing and hard to manage. Objects help group related information together, just like a real book has all its details in one place.

🎯 Goal: You will create an object to store book details, add a new property for stock count, and then print the full book information. This shows why objects are useful to keep related data organized.

📋 What You'll Learn

Create an object called book with properties title, author, and price with exact values

Add a new property stock to the book object with a number value

Use a for...in loop to go through all properties of book

Print each property and its value in the format: property: value

💡 Why This Matters

🌍 Real World

Objects are used everywhere in programming to represent real things with many details, like books, users, or products.

💼 Career

Understanding objects is essential for web development, as JavaScript uses objects to handle data, user info, and more.

1

Create the book object with details

Create an object called book with these exact properties and values: title set to "JavaScript Basics", author set to "Jane Doe", and price set to 29.99.

Javascript

// Create the book object with title, author, and price
// Your code here

Need a hint?

Use curly braces {} to create an object and separate properties with commas.

2

Add a stock property to the book object

Add a new property called stock to the existing book object and set it to the number 12.

Javascript

const book = {
  title: "JavaScript Basics",
  author: "Jane Doe",
  price: 29.99
};

// Add stock property to book
// Your code here

Need a hint?

Use dot notation to add a new property to an existing object.

3

Use a for...in loop to access all properties of book

Write a for...in loop using the variable key to go through all properties of the book object.

Javascript

const book = {
  title: "JavaScript Basics",
  author: "Jane Doe",
  price: 29.99
};

book.stock = 12;

// Loop through book properties
// Your code here

Need a hint?

Use for (const key in book) to loop over all keys in the object.

4

Print each property and its value

Inside the for...in loop, write a console.log statement to print each property and its value in the format: property: value using key and book[key].

Javascript

const book = {
  title: "JavaScript Basics",
  author: "Jane Doe",
  price: 29.99
};

book.stock = 12;

for (const key in book) {
  // Print property and value
  // Your code here
}

Need a hint?

Use a template string with backticks and ${} to insert variables inside the string.