React

React (also known as React.js or ReactJS) is a JavaScript library for building user interfaces. React can be used to create single-page software applications for web and mobile platforms. The open-source library is maintained by Meta (formerly Facebook) and a community of software engineers. Although React is a library rather than a language, it is widely used in web development. The library first appeared in May 2013 and is now one of the most commonly used front-end libraries for web development.

React in 100 Seconds by Fireship

React is easy to understand and use to build web or mobile applications because of its component-based architecture, well-defined lifecycle, and use of simple JavaScript. React also uses JSX, a unique syntax that allows developers to blend HTML and JavaScript.

React is also declarative, which means it relies on underlying components of a given language to carry out the necessary steps to reach the stated outcome, and its components are divided into two types, class components and function components.

React was created by Facebook (now Meta). React started as a JavaScript port of XHP, a version of PHP. XHP was concerned with minimizing Cross-Site Scripting (XSS) attacks. XSS attacks can involve entering content with embedded and hidden JavaScript, the language that runs inside every web browser, and then using that embedded JavaScript to steal information or compromise the user who views the content. XHP removes the burden of scrubbing user-submitted information.

However, there was a distinct problem with XHP, in that dynamic web applications required many roundtrips to the server, and XHP did not solve this problem. A Facebook (now Meta) engineer proposed a solution to take XHP into the browser using JavaScript and was granted six months to try it. The result was React.