React makes it painless to create interactive UIs. Design simple views for each state in your application, and React will efficiently update and render just the right components when your data changes. …

This funny tag syntax is neither a string nor HTML. It is called JSX, and it is a syntax extension to JavaScript. We recommend using it with React to describe what the UI should look like. JSX may …

This function is a valid React component because it accepts a single “props” (which stands for properties) object argument with data and returns a React element. We call such components …

What is the Virtual DOM? The virtual DOM (VDOM) is a programming concept where an ideal, or “virtual”, representation of a UI is kept in memory and synced with the “real” DOM by a library such …

First, let’s review how you transform lists in JavaScript. Given the code below, we use the map() function to take an array of numbers and double their values. We assign the new array returned by map() to …

Hooks are a new addition in React 16.8. They let you use state and other React features without writing a class.

What is a Hook? A Hook is a special function that lets you “hook into” React features. For example, useState is a Hook that lets you add React state to function components. We’ll learn other Hooks …

Unlike browser DOM elements, React elements are plain objects, and are cheap to create. React DOM takes care of updating the DOM to match the React elements. Note: One might confuse elements …

React has a powerful composition model, and we recommend using composition instead of inheritance to reuse code between components. In this section, we will consider a few problems where …

Context provides a way to pass data through the component tree without having to pass props down manually at every level. In a typical React application, data is passed top-down (parent to child) via …