Features
- Book and customer registration
- Lookup by ID
- Loans with availability checks
- Returns with customer checks
PROGRAMMING · TYPESCRIPT · TESTING
Library Management
A TypeScript library management system with reliable lending rules, automated tests and continuous integration.
borrowBook(customerId: number, bookId: number): string {
const customer = this.findCustomerById(customerId);
const book = this.findBookById(bookId);
if (customer && book && book.available) {
customer.borrowBook(bookId);
book.toggleAvailability();
return `${customer.name} successfully borrowed "${book.title}".`;
}
return `Borrowing failed.`;
}- Program
- Computer Programmer program · Lambton College
- Year
- 2024
- Role
- Developer
- Quality
- Jest tests + continuous integration
// 01 · THE MISSION
The mission
Library Management simulates a library's operations: registering books and customers, loans and returns. The main challenge was ensuring the system never reaches an inconsistent state—for example, lending a book that is already on loan or accepting the return of a book the customer does not have. To achieve this I applied object-oriented programming, covered every operation with Jest unit tests and set up GitHub Actions so the tests run automatically on every change. Developed within the Computer Programmer program at Lambton College in Ontario, Canada, following professional standards for development, documentation and version control.
// WHAT WAS BUILT
Architecture
- Book and Customer models
- Bookstore service with the business logic
- TypeScript compiled to JavaScript in dist/
// QUALITY
How it is guaranteed to work
Clear business rules
A book is lent only if available and returned only if the customer has it, with clear success or error messages.
Tests for every operation
Unit tests for adding, borrowing and returning books that check both the response and the final state.
Source and compiled code
Tests run on both the TypeScript code and the compiled JavaScript, ensuring the final build behaves the same way.
Continuous integration
GitHub Actions runs the tests on every push and pull request, caches dependencies and keeps the coverage report.
// TESTS
All tests passing
$ npm test PASS src/tests/addBook.test.ts PASS src/tests/borrowBook.test.ts PASS src/tests/returnBook.test.ts PASS dist/tests/addBook.test.js PASS dist/tests/borrowBook.test.js PASS dist/tests/returnBook.test.js Test Suites: 6 passed, 6 total Tests: 6 passed, 6 total
Result recorded in the repository (results.txt).
MISSION ACCOMPLISHED
Results and impact
- Lending logic with no inconsistent states
- Automatic tests on every code change
- Code organized into models and services, easy to extend
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