@invinite-org/chartlang-host-worker

experimental

Browser-default ScriptHost for chartlang. Boots a Web Worker, loads a compiled script bundle, and round-trips CandleEvent / RunnerEmissions across a structured-clone-safe postMessage protocol.

Install

pnpm add @invinite-org/chartlang-host-worker

Public surface

• createWorkerHost(opts) → ScriptHost — main-side factory; the canvas2d reference adapter (Task 10) consumes the returned host.
• DEFAULT_LIMITS — Phase-1 HostLimits defaults (maxCpuMsPerStep: 50, maxHeapBytes: 64 MiB, maxRingBufferBars: 5000, maxLoadTimeoutMs: 30000).
• idbStateStore(opts) from @invinite-org/chartlang-host-worker/idb — IndexedDB PersistentStateStore for browser warm starts.
• Persists one snapshot per StateStoreKey; default cap is 50 MiB.
• Oldest snapshots are evicted first when writes exceed the cap.
• @invinite-org/chartlang-host-worker/worker-boot — bundled worker entry for Vite / bundler new Worker(new URL(...)) patterns. Side-effect only.
• Types: ScriptHost, HostLimits, WorkerLike, HostCompiledScript, HostToWorker, WorkerToHost, CreateWorkerHostOpts.

Minimum-viable API call

import { createWorkerHost } from "@invinite-org/chartlang-host-worker";
// host: ScriptHost — passed to an adapter at construction time.

Vite worker URL

const url = new URL(
    "@invinite-org/chartlang-host-worker/worker-boot",
    import.meta.url,
);
const worker = new Worker(url, { type: "module" });
const host = createWorkerHost({ capabilities, workerLike: worker });

Stability

Phase 1 ships the postMessage wire protocol + a measurement-based CPU watchdog (step-overshoot reports observed elapsed ms; no preemption). Deferred to Phase 5 (per PLAN §19):

• Worker-side CSP enforcement.
• Hard heap caps (maxHeapBytes is advisory today — no browser API exposes a reliable per-worker heap limit).
• Real preemption via setInterruptHandler (lands with the QuickJS host).
• Fingerprint-only globals (Math.random, Date.now, …) — Phase 1 relies on the compiler's forbiddenConstructs pass to scrub these from the bundle before it ever reaches a worker.

Docs

See docs/hosts/worker.md.

License

MIT