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!

I think that looks awesome! Makes me wish I was a JS programmer so I could try it out :)

Qt has QStateMachine http://doc.qt.io/qt-5/qstatemachine.html which is modeled after State Chart XML https://www.w3.org/TR/scxml/ (but no XML is required to use it)

It's LGPLv3 if you use Qt > 5.6 (LGPLv2 earlier), and 5.6 is getting old now.

I use statemachines a lot in embedded systems and decorate the code with comments that are easy to translate into graphvizs "dot" languge.

Also played around with doing dynamic charts as the code runs, but stopped doing that as it was more novelty value than any other kind of value :)

Definitely not FOSS, but Stateflow is used a ton in scientific computing (Automotive, Control Systems, etc): https://www.mathworks.com/products/stateflow.html

Though you should always have NIHS in the back of your mind, state machines aren't very difficult to implement which means when you write yours you can really tailor it to your use case.

Statecharts are a very different beast than a traditional state machine. Putting together a good statechart implementation is a boatload of work.

Missed that part. You're correct.

JS Harel Statecharts: https://github.com/burrows/statechart.js