@seanhogg/builderforce-webcontainers

The browser runtime of BuilderForce WebContainers: boot an in-browser dev server and preview the project in an iframe. No COOP/COEP headers, no session caps, MIT licensed.

1. Serve dist/sw.js from your site, ideally at /__bfwc/sw.js so the worker's scope stays off the rest of your app. You can resolve its path with import.meta.resolve('@seanhogg/builderforce-webcontainers/sw.js'), or copy it in your build.
2. Start and write the files:

import { startPreviewRuntime } from '@seanhogg/builderforce-webcontainers';

const runtime = await startPreviewRuntime({ serviceWorkerUrl: '/__bfwc/sw.js', id: projectId });
runtime.writeTree(files);
if (runtime.profile().supported) iframe.src = runtime.url;
else showFallback(runtime.profile().reason);

To run untrusted code (AI-written, arbitrary packages), isolate the preview on its own origin with startPreviewRuntime({ relayUrl }). That origin serves relay.html, sw.js and process-worker.js (strings in @seanhogg/builderforce-webcontainers/assets) with Content-Security-Policy: frame-ancestors limited to your app. See the root README.

runtime.build({ base }) returns a deployable static site ({ files: [{ path, data }] }), and createChecker() from @seanhogg/builderforce-webcontainers/check type-checks the project in a Web Worker. .vue and .svelte files need no setup. See the root README.

The package re-exports everything from @seanhogg/builderforce-webcontainers-core.