Firebase Rules Parser

The `firebase-rules-parser` library provides a parser and emulator for Firebase security rules, allowing developers to programmatically load and test Firebase rule files. Its primary use case is facilitating unit testing for Firebase projects, particularly as a companion to `ts-mock-firebase`. The current stable version is 2.0.1, released in May 2019. While it aims to support nearly all Firebase rules language functionality, it explicitly notes limitations with duration, latlong, and timestamp functions. The project's release cadence appears to be slow or inactive since 2019, and it differentiates itself by offering an off-platform rule emulation capability without requiring a live Firebase instance, making it suitable for local development and CI/CD pipelines. It ships with TypeScript types, enhancing developer experience for TypeScript users.