@homeostate/store-ngrx-signals

NgRx Signals adapter for @homeostate/core. It keeps a slice of a signalState or signalStore in sync with a CRDT backend such as Yjs, Loro or Automerge.

Install

npm install @homeostate/core @homeostate/store-ngrx-signals @ngrx/signals @homeostate/crdt-yjs yjs

@angular/core 21 and @ngrx/signals 21 are peer dependencies.

Usage

injector is required: it owns the state watcher, so the engine can reconnect outside an injection context. Capture it with inject(Injector):

import { DestroyRef, inject, Injector } from "@angular/core";
import { patchState, signalState } from "@ngrx/signals";
import { createSyncEngine } from "@homeostate/core";
import { createNgrxSignalsAdapter } from "@homeostate/store-ngrx-signals";
import { createYjsBackend } from "@homeostate/crdt-yjs";
import * as Y from "yjs";

const state = signalState({ shared: { count: 0 }, panelOpen: false });
const doc = new Y.Doc();
const adapter = createNgrxSignalsAdapter(state, {
  select: (state) => state.shared,
  replace: (shared) => patchState(state, { shared }),
  injector: inject(Injector),
});
const engine = createSyncEngine(createYjsBackend(doc, "counter"), adapter);
engine.connect();

patchState(state, ({ shared }) => ({ shared: { count: shared.count + 1 } }));

inject(DestroyRef).onDestroy(() => {
  engine.disconnect();
  doc.destroy();
});

Attach a Yjs provider to doc for replication, and destroy it on teardown too.

• select must return the same object until the slice changes, so update the slice immutably and never build a new object in select.
• replace must replace the slice completely, including removing absent keys. patchState shallow-merges, so keep synced data under one key, such as shared, and replace that key.
• For a protected signalStore, create the adapter inside withHooks or withMethods, or pass a public replacement method as replace.

Disconnecting the engine, or destroying the injector, removes the watcher. Disconnecting the engine and destroying the document stay yours to do.

See the Angular playground for a complete demo.