Book model

Design book and member types.

Book model

We define three core types for a library. Book represents a book: id, title, author, and available (loan status). Member represents a member: id and name. Library holds an array of books.

interface Book { id: string; title: string; author: string; available: boolean; }
interface Member { id: string; name: string; }
interface Library { books: Book[]; }

Empty library

An empty library is a Library object whose books field is an empty array. The array grows as you add books.

const lib: Library = { books: [] };
console.log(lib.books.length);  // 0

Exercise Write the library model

Define a Book interface: id: string, title: string, author: string, available: boolean. Define a Member interface: id: string, name: string. Define a Library interface: books: Book[]. Create an empty library and print the number of books.

Show example solution

interface Book { id: string; title: string; author: string; available: boolean; }
interface Member { id: string; name: string; }
interface Library { books: Book[]; }

const lib: Library = { books: [] };
console.log(lib.books.length);

Test yourself

Which field tracks whether a book is borrowed?
- available (boolean)
- title
- author
- id
Show answer

available (boolean) — The available field is true when the book is on the shelf and false when it is borrowed. title, author, and id do not track loan status.

Complete the Book field

interface Book { id: string; title: string; author: string; ____: boolean; }

Show answer

interface Book { id: string; title: string; author: string; available: boolean; }

Library model parts

Book

Book details (id, title, author, available)
Member

Member details (id, name)
Library

Book collection
available: boolean

Loan status

Next lesson: Add and search

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies