react-lazy-cache is a utility to lazily calculate and cache values in a React component based on props. Ideally, in a React component, you would calculate values that depend on your props inputs every time the component is rendered. However, in practice, sometimes these values, either for computational or memory reasons, are better off cached. When you cache them, however, you need to be constantly watching your props to know if you need to invalidate your cache and recalculate those values. That is what react-lazy-cache does for you.