What Is React?

React is a declarative, efficient, and flexible JavaScript library for building user interfaces. It lets you compose complex UIs from small and isolated pieces of code called “components”.

Passing Data Through Props

To get our feet wet, let’s try passing some data from our Board component to our Square component.

We strongly recommend typing code by hand as you’re working through the tutorial and not using copy/paste. This will help you develop muscle memory and a stronger understanding.

Function Components

The simplest way to define a component is to write a JavaScript function:

function Welcome(props) {
  return <h1>Hello, {props.name}</h1>;
}

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 “function components” because they are literally JavaScript functions.

Create a Next.js App

Enter Next.js, the React Framework. Next.js provides a solution to all of the above problems. But more importantly, it puts you and your team in the pit of success when building React applications.

Next.js is used in tens of thousands of production-facing websites and web applications, including many of the world’s largest brands.