React Tween State Animation Library

react-tween-state is an animation utility for React applications that enables smooth interpolation of component state values over time. It provides a `this.tweenState` method, which functions similarly to `this.setState`, but initiates an animated transition of a state property to a target value over a specified duration. The library relies heavily on React's deprecated mixin system (`React.createClass`) for integration into components. The current and likely final stable version is 0.1.5, released in 2016, and the project has been unmaintained since then. Its core differentiators, such as direct state manipulation via mixins and an imperative `tweenState` API, are now considered anti-patterns in modern React development, which favors declarative component-based animation libraries and hooks. It does not support newer React features or functional components.