scxmljs

@tinyactors/scxmljs is a correctness-first SCXML 1.0 interpreter for the ECMAScript data model. It runs directly on DOM elements, and comes with custom elements that render running statecharts in any framework.

• Correct: all 160 automatic mandatory W3C conformance tests pass, with either data model.
• Two data models, one API:
  • sandboxed (QuickJS compiled to WebAssembly, one context per session) for charts users write;
  • trusted (the host's own JavaScript engine, about 15 KB gzipped) for charts you ship yourself.
• Built for visualisation: typed events, a playback clock that can pause and step, and a view-model for the system, tree and focus views of a running chart.

Full-resolution video (WebM, 2880×1800) · High-resolution screenshot (PNG) · the explorer with the optional Tinyactors theme

Docs & demos: https://scxmljs.tinyactors.dev: the guides, live demos, the API reference and search. In the repository: the package README (also the npm page), the guides, SECURITY.md and the changelog.

Repository layout

Path	What
packages/scxmljs/	the library
examples/playground/	demo app: the explorer with sample systems, <scxml-view>, a GitHub-webhook example
examples/frameworks/	small React, Vue, Svelte and Angular apps using both elements
conformance/	the W3C SCXML conformance suite, vendored (ecma/), with its runner and fetcher
tests/browser/	Playwright tests (Chromium, Firefox, WebKit), including screenshot baselines
docs/	guides, reference and the examples they use
bench/	benchmark charts and recorded results (docs/measurements.md is generated from them)
scripts/	CI (scripts/ci), the release dry run (scripts/release), doc tests and link checks (scripts/docs/), size, coverage, benchmarks
tools/typedoc/	the API-reference generator, with its own TypeScript 5 (see docs/README.md)

Running it

Requires mise and Bun.

bun install
mise run test                  # unit tests
mise run typecheck
mise run conformance           # W3C suite, sandboxed data model (vendored: no network)
mise run conformance:trusted   # W3C suite, trusted data model
mise run up                    # playground on http://localhost:4321 (mise run down to stop)
mise run docs:test             # run every code sample in the docs
mise run docs:api              # API reference into docs/api
scripts/ci                     # light checks (every push and pull request)
scripts/ci --full              # + browsers, visual regression, framework apps, tarball (release preparation)
scripts/release                # release dry run: checks, packs and verifies; never publishes

Contributions

This project doesn't accept outside contributions: pull requests and issues won't be reviewed. You're welcome to fork it under the terms of the licence.