React

JavaScript library for building user interfaces

React (also known as React.js or ReactJS) is an open-source JavaScript library for building user interfaces or UI components. It is maintained by Meta (formerly Facebook) and a community of individual developers and companies. React can be used as a base in the development of single-page or mobile applications. However, React is only concerned with state management and rendering that state to the DOM, so creating React applications usually requires the use of additional libraries for routing, as well as certain client-side functionality.

History

React was created by Jordan Walke, a software engineer at Facebook. It was first deployed on Facebook's News Feed in 2011 and later on Instagram in 2012. It was open-sourced at JSConf US in May 2013.

Features

React's main features include:

• **Declarative**: 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.
• **Component-Based**: Build encapsulated components that manage their own state, then compose them to make complex UIs.
• **Learn Once, Write Anywhere**: You can develop new features in React without rewriting existing code. React can also render on the server using Node.js, and it can power mobile apps using React Native.

JSX

React components are typically written using JSX, a syntax extension that allows mixing HTML with JavaScript. JSX is compiled to JavaScript before being executed in the browser.

Virtual DOM

React uses a virtual DOM to improve performance. The virtual DOM 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 as ReactDOM. This process is called reconciliation.

Ecosystem

React has a rich ecosystem of libraries and tools, including:

• **Redux**: A predictable state container for JavaScript apps.
• **React Router**: A collection of navigational components that compose declaratively with your application.
• **Next.js**: A React framework for server-side rendering and generating static websites.

See also

• Angular (web framework)
• Vue.js
• Svelte (JavaScript framework)
• JavaScript framework
• Single-page application

External links

• Official website