Book Image

Designing React Hooks the Right Way

By : Fang Jin
Book Image

Designing React Hooks the Right Way

By: Fang Jin

Overview of this book

React hook creates a unique solution for using states in function components to orchestrate UI communication. They provide you with an easy interface to write custom data management solutions with low development and maintenance costs. Understanding how Hooks are designed enables you to use them more effectively, and this book helps you to do just that. This book starts with a custom-crafted solution to reveal why Hooks are needed in the first place. You will learn about the React engine and discover how each built-in Hook can manage a persistent value by hooking into it. You will walk through the design and implementation of each hook with code so that you gain a solid understanding. Finally, you'll get to grips with each Hook's pitfalls and find out how to effectively overcome them. By the end of this React book, you'll have gained the confidence to build and write Hooks for developing functional and efficient web applications at scale.
Table of Contents (12 chapters)

Test-Driving useMemo

Let's improve the example that we saw at the beginning of the chapter with the useMemo hook to gain some performance:

const Title = ({ text, flag }) => {
  const found = useMemo(() => {
    console.log('created')         ➀
    return matchTextInArray(text))
  }, [text])  
  console.log('updated', found)    ➁

The preceding code replaces useState and useEffect with useMemo. Let's take a look at the timeline to see what difference it makes:

|----TFTF--------TF------> flag
----------a---------b----> text
R----RRRR-R---------R----> updated ➁
c---------c---------c----> created ➀

A new value is created in the "created" series when the text changes, independent of the flag flips. Even better this time, there&apos...