The concept of immutability is important, with respect to maintaining the predictability of the state, the performance of the component, and an easier deep-nested comparison. In this chapter, we explored the need for immutability, and how we can exploit its use in React and Redux applications. In addition to that, you learned how we can configure Immutable JS, integrate it with our applications and finally, test our Immutable JS code.

In the next chapter, we will combine the concepts that you have learned about Redux, from Chapter 1, Understanding Redux; Chapter 2, Testing; and this chapter (on Immutable JS), and create the base of our application. We will dig more deeply into React and how it can amalgamate with Redux.