React Transition Group

React Transition Group is a set of low-level primitive components for managing component states over time, specifically designed to facilitate animations in React applications. It enables developers to define and control lifecycle events for components entering, exiting, or remaining in the DOM. The current stable version is 4.4.5, last updated in August 2022, with a release cadence focused on stability and compatibility with React's evolving ecosystem. This library doesn't dictate specific animation libraries or CSS frameworks; instead, it provides hooks and class toggles (`CSSTransition`) that allow integration with arbitrary CSS transitions/animations or JavaScript animation libraries. Its key differentiator is providing an unopinionated, foundational API for animation patterns, contrasting with higher-level animation libraries that often bundle their own animation engines or opinions.