Book Image

React Key Concepts

By : Maximilian Schwarzmüller
Book Image

React Key Concepts

By: Maximilian Schwarzmüller

Overview of this book

As the most popular JavaScript library for building modern, interactive user interfaces, React is an in-demand framework that’ll bring real value to your career or next project. But like any technology, learning React can be tricky, and finding the right teacher can make things a whole lot easier. Maximilian Schwarzmüller is a bestselling instructor who has helped over two million students worldwide learn how to code, and his latest React video course (React — The Complete Guide) has over six hundred thousand students on Udemy. Max has written this quick-start reference to help you get to grips with the world of React programming. Simple explanations, relevant examples, and a clear, concise approach make this fast-paced guide the ideal resource for busy developers. This book distills the core concepts of React and draws together its key features with neat summaries, thus perfectly complementing other in-depth teaching resources. So, whether you've just finished Max’s React video course and are looking for a handy reference tool, or you've been using a variety of other learning materials and now need a single study guide to bring everything together, this is the ideal companion to support you through your next React projects. Plus, it's fully up to date for React 18, so you can be sure you’re ready to go with the latest version.
Table of Contents (16 chapters)

Managing State with useReducer()

Just like useState(), useReducer() is a React Hook. And just like useState(), it is a Hook that can trigger component function re-evaluations. But, of course, it works slightly differently; otherwise, it would be a redundant Hook.

useReducer() is a Hook meant to be used for managing complex state objects. You will rarely (probably never) use it to manage simple string or number values.

This Hook takes two main arguments:

  • A reducer function
  • An initial state value

This brings up an important question: what is a reducer function?

Understanding Reducer Functions

In the context of useReducer(), a reducer function is a function that itself receives two parameters:

  • The current state value
  • An action that was dispatched

Besides receiving arguments, a reducer function must also return a value: the new state. It's called a reducer function because it reduces the old state (combined with an action) to a new...