Appendix

Appendix A – React Fiber

During the user session with a website, a series of actions is generated. We'd expect to have these actions dispatched and have changes applied back to the Document Object Model (DOM). This cycle is what makes it a typical web experience.

Figure 3.6 – React Fiber with Render and Commit phrases

What React does for us is to allow the dispatched action to update the changes to be reflected on the screen. React splits each update into two major phrases, the Render and the Commit, illustrated in the preceding figure. What a render does is go through all elements one by one and collect all the changes, whereas a commit applies the changes to the UI in one shot.

This engine has a codename, Fiber. To facilitate all this, React creates an internal object called a fiber to represent each element. As we have introduced, the element can be a classical element, such as a DOM element, or an artificial one, such...