@nexus_js/sync

Nexus Local-First Sync — two tracks:

1. $localSync / syncEngine — IndexedDB + JSON ops queue + fetch flush (production-ready baseline).
2. Byte-Mirror (prototype) — SQLite WASM inside a dedicated Web Worker, with OPFS persistence when the host sends COOP/COEP headers (otherwise :memory: fallback).

Byte-Mirror (SQLite worker)

import {
  ByteMirrorBridge,
  resolveSqliteSyncWorkerUrl,
} from '@nexus_js/sync';

const bridge = new ByteMirrorBridge(resolveSqliteSyncWorkerUrl());
await bridge.init();
await bridge.upsertNode({
  id: 'n1',
  flowId: 'f1',
  x: 120,
  y: 40,
  data: { label: 'Start' },
});
const rows = await bridge.listNodes('f1');
const outbox = await bridge.drainOutbox(20);
// POST `outbox[].frame_json` to your Server Action, then:
await bridge.markOutboxSynced(outbox.map((r) => r.id));

Security: the worker never executes arbitrary SQL from the page — only whitelisted ops (UPSERT_NODE, DELETE_NODE, …).

OPFS: for durable local SQLite, serve your app with:

• Cross-Origin-Opener-Policy: same-origin
• Cross-Origin-Embedder-Policy: require-corp (or credentialless if compatible with your assets)

Bundlers: prefer new Worker(new URL('@nexus_js/sync/workers/sqlite-sync.worker.js', import.meta.url), { type: 'module' }) or Vite’s ?worker so @sqlite.org/sqlite-wasm and .wasm resolve correctly.

Next steps (not in this package yet): binary ChangeSet protocol, server-side merge / LWW, AES-GCM at rest, and a compiler-backed $mirror rune.

Documentation

All guides, API reference, and examples live on nexusjs.dev.

Links

• Website: https://nexusjs.dev
• Repository: github.com/bierfor/nexus (see packages/sync/)
• Issues: github.com/bierfor/nexus/issues

License

MIT © Nexus contributors