Testing in TypeScript

This book is a comprehensive guide to testing web applications in TypeScript. It is intended for developers who are already familiar with the basics of TypeScript and want to learn how to write reliable, maintainable tests for their projects. The book covers all stages of testing: from unit tests to integration and e2e tests.

The reader will learn how to set up a testing environment, choose suitable frameworks (Jest, Mocha, Cypress, Playwright), write clean and effective tests, use mocks and stubs, test asynchronous code, work with TypeScript types in tests, and automate the code quality verification process. Special attention is paid to best practices and testing patterns, as well as integrating tests into CI/CD pipelines.

Chapter contents include: introduction to testing and TypeScript, setting up the test environment, unit testing of functions and classes, testing React components, testing APIs and server-side code, end-to-end testing, working with mocks and stubs, testing asynchronous operations and events, code coverage and report analysis, as well as advanced topics — testing with DI, dependency injection, and writing custom matchers.

Why should you read this book? It not only teaches how to write tests but also forms the correct mindset of a tester and developer, helping to create stable and easily maintainable projects. Practical examples in TypeScript, analysis of real-world cases, and ready-made test templates will allow you to immediately apply the acquired knowledge in your work. The book will be useful for both frontend and backend developers striving to improve the quality of their code.