I created XState, a JS/TS library for authoring, executing, and visualizing state machines/statecharts: https://github.com/statelyai/xstate
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...
If this is the first time you're hearing about Statecharts, I highly recommend the book "Constructing the user interface with statecharts" by Ian Horrucks (https://archive.org/details/isbn_9780201342789/mode/2up) which yes, is from 1999, but probably the best introduction for how to actually apply and use Statecharts.
It'll take some time for those apps/tools to realize the full potential of statecharts, but it's a good start.
Yes, I stumbled upon statecharts checking out this Godot plugin: https://github.com/derkork/godot-statecharts
I often have my AI code output one just to make sure my logic feels more sound. Along with mermaid charts if I need to toy around or drop into stately for more power.
Created StateKit for ObjC/Swift some time ago, it’s been production tested in some very large apps: https://github.com/sghiassy/StateKit
Such a cool data structure
Having visual understanding of state is becoming increasingly important for AI generated code you don't nearly understand as well as the human variety.
It seems many still favor store based reactivity state in frontend frameworks.
I contribute to it being the default so why change and because libraries like xstate are far more difficult to learn the syntax and are more verbose. But with AI that's hardly an issue, so I wonder if there is more to it I don't see and we just haven't seen the state chart reach it's peak yet.
But at the same time, frontier models are very good at writing XState.