Koa IP Filter Middleware

The `koa-ip` package provides a robust IP filtering middleware specifically designed for Koa applications. It allows developers to manage network access by configuring either a `whitelist` to permit specific IP addresses or a `blacklist` to deny them. The package accommodates both literal IP strings and regular expressions for defining patterns, enabling flexible control over single IPs, IP ranges, or subnets. Currently stable at version 2.1.4, `koa-ip` exhibits a stable release cadence, typical for well-defined utility middleware, suggesting ongoing maintenance rather than rapid feature development. Its key differentiators include a minimalist API, seamless integration into the Koa middleware chain, and built-in TypeScript definitions, making it easy to adopt in modern Koa projects. By default, it returns a 403 Forbidden status for blacklisted IPs, a behavior that can be customized with an asynchronous handler function, offering fine-grained control over denied requests.