Hey! I'm the creator of xstate: https://github.com/davidkpiano/xstate - a pure, functional, declarative implementation of statecharts in TypeScript. It has zero dependencies, is frameworkless, and fast (O(n) state and transition look-up time for most cases).

I have some important updates to announce at JSConf Iceland, including the ability to translate to/from SCXML, and an improved visualizer.

Let me know what you think!