Interstate

A live editor for creating interactive web applications.

Run locally

Use Node.js 24 LTS (Node.js 22 is also tested). No Ruby, native Sass compiler, Grunt installation, or third-party CDN is needed.

npm ci
npm run build
npm start

Open http://127.0.0.1:8000 for the project homepage, choose Open Editor, then click edit to open the editor. Allow the editor popup if your browser prompts. Programs are saved in the browser's local storage; use the editor's export feature for backups. Keep the same site origin to retain access to existing saved programs.

PORT and HOST configure the server. For containers or access from another computer, use HOST=0.0.0.0 npm start. npm run dev additionally enables the legacy test pages. Re-run the build after source changes.

Verify changes

npm ci
npx playwright install chromium firefox webkit
npm test

The checks rebuild the site, exercise HTTP routes, open the runtime and popup editor in Chromium, Firefox, and WebKit, verify saving/reloading and remote session reconnection, exercise Breakout movement, and run the legacy QUnit suite. Static-host checks serve only .build/ under a subdirectory and verify both editor popups and tutorial navigation. Linux machines may need npx playwright install --with-deps chromium firefox webkit. The old heap-snapshot tests require their original browser extension for actual memory-leak measurement; without it, they only exercise the functional paths.

GitHub Actions runs checks on pushes, pull requests, and weekly on Node 22 and 24. Successful Node 24 runs publish an interstate-site artifact. Pushes to master and manual runs on master deploy that exact artifact to GitHub Pages only after both Node versions pass all three browser engines. Failed checks leave the previous site deployed. Dependabot proposes dependency updates; merge them only after checks pass. Exact versions and package-lock.json make installs repeatable. Vendored browser libraries remain checked in for compatibility and need deliberate, tested updates.

The vendored ConstraintJS solver includes a regression-tested guard against re-entering a getter while it is constructing its value. Preserve this fix when updating that library. Runtime regression checks also cover DOM event batching and non-bubbling events. The Breakout sample initializes its position before following physics coordinates; moving those expressions back to its initial state creates a circular dependency.

Browser support

The automated suite covers the current Chromium, Firefox, and WebKit engines, including the runtime, popup editor, saving, examples, and tutorial. These cover the engines used by Chrome/Edge, Firefox, and Safari. WebKit automation is not an actual Safari installation. Old browsers and every browser/device combination cannot be guaranteed; keep the browser tests and Playwright updates passing to catch compatibility regressions.

Deploy

GitHub Pages must use GitHub Actions as its publishing source. The workflow in .github/workflows/ci.yml publishes .build/ to https://soney.github.io/interstate/ with HTTPS. The old gh-pages branch is no longer the publishing source. To roll back, revert the faulty source commit on master and let the checks and deployment run again.

npm run build produces the complete static site in .build/. The project homepage and public navigation live in site/; the runtime is published at build/, preserving the historical build/index.html?open=..., breakout/, drag_lock/, image_carousel/, and touch_map/ links. Do not replace the public homepage with the runtime's intentionally empty canvas. Root editor/tutorial assets remain available for links shared during the earlier deployment. Upload its contents to an HTTPS static host; do not serve the repository or dist/ directly. All core scripts, CSS, and fonts are local, so HTTPS pages work without CDN access. Example projects can still reference external content.

For a Node host, run npm ci && npm run build, then npm start under the host's process supervisor. Set HOST=0.0.0.0 and the host-provided PORT, terminate HTTPS at the proxy, and forward WebSocket connections if using remote editing. /healthz is available for health monitoring. The runtime defaults to a local popup editor on all devices, which also works on static hosting. Remote editing via Socket.IO requires the Node server and an explicitly configured external editor; it is not an authenticated collaboration service.

The optional DEPLOY_TARGET=user@host:/path/ ./upload.sh runs installation and all tests before copying the build. Prefer your host's atomic release mechanism for deployments that must not expose a partially uploaded release. Retain the previous build for rollback.

The historical address is interstate.from.so. Hosting and DNS must be configured separately; repository changes cannot repair missing DNS records. After deployment, check the public HTTPS URL and editor popup, then configure an uptime monitor against that URL (or /healthz on a Node host).

Contact: Stephen Oney (soney@cmu.edu).