Book excerpt: Learn how to structure your application state, describe events with actions and perform deterministic state transitions with reducers. State management with NgRx follows the Redux pattern and is used by hundreds of companies to build maintainable Angular applications. In combination with TypeScript and RxJS it empowers you to write testable business logic and explicit side-effects for talking to servers through HTTP or WebSockets. With immutability as a core concept you also gain performance benefits, eventually giving you the best of both worlds: lightning fast applications that are easy to maintain and grow. We'll be building an example application with the most recent versions of Angular & NgRx while getting to know all aspects of NgRx, how they fit together and which best practices you should apply. The code examples in the book are accompanied by a hosted repository where you can follow along each step of the way and jump into live demos in the browser.