Ask HN: Best Event-Driven Finite-State Machine Learning Resources

I am working on an existing typescript backend service that receives events and takes actions based on those events. I would like to further my understanding of event driven finite state machines, so that I can apply well known patterns in hopes of improving maintainability and reliability of existing services. I am also keenly interested in deepening my understanding of state machines and modern design philosophy, so that I may design future systems that are highly reliable and maintainable.

What resources do you recommend? I am a book lover, so I am happy spending money on books, but I am interested in any and all resources, including online course-ware.