davidkpiano

I've been working on it for 10+ years. The main thing I've learned is that statecharts are most valuable when they're treated as executable behavior, not just documentation.

That doesn't mean you need to use them everywhere or model everything with them. They're most useful when you have behavior where the answer to "what happens next?" depends on both the current state & the event. A statechart can act as an oracle for questions like: "Given I'm in this state, when this event happens, what is the next state, and what effects should run?"

I'm close to releasing an alpha of the next major version of XState, focused on better ergonomics, type safety, and composability, as well as a new visualizer/editor.

There's also an open-source basic statechart visualizer here: https://sketch.stately.ai

For the formal/spec side, SCXML is worth reading: https://www.w3.org/TR/scxml

Also worth reading the original paper by David Harel: https://www.weizmann.ac.il/math/harel/sites/math.harel/files...

Comment · 8 months ago

Really appreciate you using XState!

Comment · 8 months ago

Really cool! Love the XState-inspired API ;-)

Comment · 1 year ago

Re: atoms + learning curve, this is why XState Store exists, which supports both XState-style state updates and atoms: https://stately.ai/docs/xstate-store

I also like the approach of Svelte, and realize that sometimes a full state machine isn't needed. I don't think that atoms should be used everywhere, since updating state freely without guardrails just leads to disaster long-term.

Comment · 1 year ago

Thank you for the kind words! I somewhat agree that it is complicated and overly engineered for many applications that don't need all of the statechart features, and that it has a sizable learning curve.

I plan on greatly simplifying it for the next major version, mostly to be more idiomatic and flexible without sacrificing the state machine principles.

Comment · 2 years ago

I remember this! It was one of my inspirations for creating a hierarchical state machine editor [0] and a state machine library with a visualization layer [1].

[0] https://state.new [1] https://github.com/statelyai/xstate

Comment · 2 years ago

Hey thanks for linking, I'm still working on this and hope to have a beta release soon!

Stately Agent is a completely open-source library for creating (LLM) agents that adhere to state machines.