Creating type aliases in Typescript - Try It Yourself

Creating type aliases

📖 Scenario: You are building a simple program to manage a list of books in a library. Each book has a title and an author.

🎯 Goal: Create a type alias for a book object, then use it to define a list of books and print their titles.

📋 What You'll Learn

Create a type alias called Book with properties title and author, both strings.

Create a variable called library which is an array of Book objects.

Add at least two books to the library array with exact titles and authors.

Use a for loop to print each book's title.

💡 Why This Matters

🌍 Real World

Type aliases help you clearly define the shape of data objects, making your code easier to understand and less error-prone.

💼 Career

Many programming jobs require working with typed data structures to build reliable applications, especially in TypeScript.

1

Create the Book type alias

Create a type alias called Book with two string properties: title and author.

Typescript

// Your code here

Need a hint?

Use the type keyword to create a type alias with properties.

2

Create the library array

Create a variable called library that is an array of Book objects. Add these two books exactly: { title: "The Hobbit", author: "J.R.R. Tolkien" } and { title: "1984", author: "George Orwell" }.

Typescript

type Book = {
  title: string;
  author: string;
};

// Your code here

Need a hint?

Use const library: Book[] = [...] to create the array with the two book objects.

3

Loop through library to print titles

Use a for loop with variable book to iterate over library and print each book's title using console.log.

Typescript

type Book = {
  title: string;
  author: string;
};

const library: Book[] = [
  { title: "The Hobbit", author: "J.R.R. Tolkien" },
  { title: "1984", author: "George Orwell" }
];

// Your code here

Need a hint?

Use for (const book of library) to loop and console.log(book.title) to print.

4

Print the book titles

Run the program to print the titles of the books in library. The output should be exactly:
The Hobbit
1984

Typescript

type Book = {
  title: string;
  author: string;
};

const library: Book[] = [
  { title: "The Hobbit", author: "J.R.R. Tolkien" },
  { title: "1984", author: "George Orwell" }
];

for (const book of library) {
  console.log(book.title);
}

// Your code here to print output (already done)

Need a hint?

Run the program and check the console output matches the two book titles on separate lines.