React is officially defined as a “JavaScript library for creating user interfaces,” but what does that mean?

React is a library, made in JavaScript and which we code in JavaScript, to build great applications that run on the web.

What do I need to know for React?

In other words, you need a basic understanding of JavaScript to become a solid React programmer.

The most basic JavaScript concepts you should be familiar with are variables, basic data types, conditionals, array methods, functions, and ES modules,

If React was made in JavaScript, why don’t we use JavaScript?

React was written in JavaScript, which was built from the ground up for the express purpose of building web applications and gives us tools to do so.

JavaScript is a 20 years-old language that was created for adding small bits of behavior to the browser through scripts and was not designed for creating complete applications.

In other words, while JavaScript was used to create React, they were created for different purposes.

Can use JavaScript in React applications

Yes! Any valid JavaScript code can be included within your React applications.

You can use any browser or window API, such as geolocation or the fetch API.

Also, since React (when it is compiled) runs in the browser, you can perform common JavaScript actions like DOM querying and manipulation.