Introduction

In the previous chapters, you learned how to build UIs with the help of React components. You also learned about props—a concept and feature that enables React developers to build and reuse configurable components.

These are all important React features and building blocks, but with these features alone, you would only be able to build static React apps (that is, web apps that never change). You would not be able to change or update the content on the screen if you only had access to those features. You also would not be able to react to any user events and update the UI in response to such events (for instance, to show an overlay window upon a button click).

Put in other words, you would not be able to build real websites and web applications if you were limited to just components and props.

Therefore, in this chapter, a brand-new concept is introduced: state. State is a React feature that allows developers to update internal data and trigger a UI update...