Nested objects in Javascript - Mini Project: Build & Apply

Nested objects

📖 Scenario: You are managing a small library system. Each book has details like title, author, and availability status inside nested objects.

🎯 Goal: You will create a nested object to store book information, add a configuration for checking availability, extract titles of available books, and finally display those titles.

📋 What You'll Learn

Create a nested object with exact book details

Add a variable to check if a book is available

Use a loop to collect titles of available books

Print the list of available book titles

💡 Why This Matters

🌍 Real World

Nested objects are common when storing detailed information like user profiles, product catalogs, or library systems.

💼 Career

Understanding nested objects and how to access them is essential for frontend and backend developers working with JSON data and APIs.

1

Create the nested object with book details

Create a constant object called library with two books: book1 and book2. Each book should be an object with these exact properties and values: title as a string, author as a string, and status as an object with a boolean property available. Use these exact values: book1: title "The Great Gatsby", author "F. Scott Fitzgerald", available true; book2: title "1984", author "George Orwell", available false.

Javascript

// Your code here

Need a hint?

Remember to nest the status object inside each book object.

2

Add a variable to check availability

Create a constant called isAvailable and set it to the available property of book1 inside the library object.

Javascript

const library = {
  book1: {
    title: "The Great Gatsby",
    author: "F. Scott Fitzgerald",
    status: {
      available: true
    }
  },
  book2: {
    title: "1984",
    author: "George Orwell",
    status: {
      available: false
    }
  }
};
// Your code here

Need a hint?

Access nested properties using dot notation like library.book1.status.available.

3

Collect titles of available books

Create an empty array called availableBooks. Use a for...in loop with variable bookKey to iterate over library. Inside the loop, check if library[bookKey].status.available is true. If yes, push library[bookKey].title into availableBooks.

Javascript

const library = {
  book1: {
    title: "The Great Gatsby",
    author: "F. Scott Fitzgerald",
    status: {
      available: true
    }
  },
  book2: {
    title: "1984",
    author: "George Orwell",
    status: {
      available: false
    }
  }
};

const isAvailable = library.book1.status.available;

// Your code here

Need a hint?

Use for...in to loop over object keys and check nested properties inside the loop.

4

Display the available book titles

Write a console.log statement to print the availableBooks array.

Javascript

const library = {
  book1: {
    title: "The Great Gatsby",
    author: "F. Scott Fitzgerald",
    status: {
      available: true
    }
  },
  book2: {
    title: "1984",
    author: "George Orwell",
    status: {
      available: false
    }
  }
};

const isAvailable = library.book1.status.available;

const availableBooks = [];
for (const bookKey in library) {
  if (library[bookKey].status.available) {
    availableBooks.push(library[bookKey].title);
  }
}
// Your code here

Need a hint?

Use console.log(availableBooks) to show the array in the console.