In the previous chapter, we created complex component hierarchies. We created a list of pages and a way to edit those pages. Yet we stopped short of saving and reading any of that data to some kind of storage.

We could, for instance, send an edit through an Ajax request to be saved in a database server. In fact, that's what often happens in the applications we use these days. They always save our interactions, irrespective of whether we expect them to or not.

In this chapter, you will learn about local data stores and communicating with them. You'll also learn about event-based architecture and how it promotes the unidirectional flow of data.

There are many ways to save data. It's a rich and interesting topic that could fill scores of books. I could go so far as to say it is at the core of how businesses and applications work.

Furthermore, how data is communicated can often be different in a maintainable application and an unmaintainable application....