The **raptor‑cache** library offers a flexible, asynchronous caching layer that can hold data in memory, on disk, or across multiple tiered stores, while preventing duplicate work by “holding” cache entries until their values are ready. It’s ideal for developers who need to cache expensive asynchronous operations—such as API calls, file reads, or database queries—in Node.js applications, especially those that require configurable storage back‑ends (in‑memory, disk, or external services like Redis).