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Learn React Hooks

You're reading from   Learn React Hooks Build and refactor modern React.js applications using Hooks

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Product type Paperback
Published in Oct 2019
Publisher Packt
ISBN-13 9781838641443
Length 426 pages
Edition 1st Edition
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Author (1):
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Daniel Bugl Daniel Bugl
Author Profile Icon Daniel Bugl
Daniel Bugl
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Table of Contents (19) Chapters Close

Preface 1. Section 1: Introduction to Hooks
2. Introducing React and React Hooks FREE CHAPTER 3. Using the State Hook 4. Writing Your First Application with React Hooks 5. Section 2: Understanding Hooks in Depth
6. Using the Reducer and Effect Hooks 7. Implementing React Context 8. Implementing Requests and React Suspense 9. Using Hooks for Routing 10. Using Community Hooks 11. Rules of Hooks 12. Building Your Own Hooks 13. Section 3: Integration and Migration
14. Migrating from React Class Components 15. Redux and Hooks 16. MobX and Hooks 17. Assessments 18. Other Books You May Enjoy

Preventing unnecessary re-rendering with React.memo

With class components we had shouldComponentUpdate, which would prevent components from re-rendering if the props did not change.

With function components, we can do the same using React.memo, which is a higher-order component. React.memo memoizes the result, which means that it will remember the last rendered result, and, in cases where the props did not change, it will skip re-rendering the component:

const SomeComponent = () => ...

export default React.memo(SomeComponent)

By default, React.memo will act like the default definition of shouldComponentUpdate, and it will only shallowly compare the props object. If we want to do a special comparison, we can pass a function as a second argument to React.memo:

export default React.memo(SomeComponent, (prevProps, nextProps) => {
// compare props and return true if the props...
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