React 16 Essentials - Second Edition

Chapter 7. Updating Your React Components

In the previous chapter, you learned that a React component can go through three phases:

• Mounting
• Updating
• Unmounting

We've already discussed the mounting and unmounting phases. In this chapter, we'll focus on the updating phase. During this phase, a React component is already inserted into the DOM. This DOM represents a component's current state, and when that state changes, React needs to evaluate how a new state is going to mutate the previously rendered DOM.

React provides us with methods to influence what is going to be rendered during an update as well as to be aware of when an update happens. These methods allow us to control the transition from the current component's state to the next component's state. ...