React JS, often simply referred to as React, is a popular open-source JavaScript library used for building user interfaces, particularly for single-page applications. Developed and maintained by Facebook, React enables developers to create reusable UI components that manage their own state, leading to a more efficient and manageable development process. Its component-based architecture allows for the creation of complex UIs by breaking them down into simpler, isolated pieces that can be independently developed and tested. React also employs a virtual DOM (Document Object Model) which enhances performance by updating only the parts of the DOM that have changed, rather than re-rendering the entire page. This combination of features makes React a powerful tool for developing dynamic and responsive web applications.
