In this chapter, you learned how to design and implement an architecture for your Immutable.js abstraction. We started by building a reusable component that takes the initial application state and side-effect functions as arguments and returns an updater function, which is then used throughout the application to update the application state. This component runs the appropriate side-effect whenever state changes.

Then you implemented another version of the application from Chapter 14, Side-Effects in User Interfaces, where we listed Black Mirror episodes. This implementation used our new App() component to encapsulate immutable state and to orchestrate the execution of our side-effect functions.

I hope this has been an enlightening read. I set out to write this book with the hope of sharing some of my hard-earned knowledge working with Immutable.js in production for many years. With the skills you've picked up in this book, I'm confident that you'll be able to tackle any problem that comes your way by wielding Immutable.js collection awesomeness.