@nomyx/canton-projection

Projection engine for streaming Canton ledger events into pluggable stores.

Installation

npm install @nomyx/canton-projection @nomyx/canton-sdk ws

Quick Start

import { ProjectionEngine, InMemoryStore } from '@nomyx/canton-projection';
import { CantonClient, SandboxAuth } from '@nomyx/canton-sdk';

const client = new CantonClient({
  ledgerUrl: 'http://localhost:7575',
  auth: new SandboxAuth('Alice'),
});

const store = new InMemoryStore();

const engine = new ProjectionEngine({ client, store });

// Map ledger events to store records
engine.register('Main:Asset', {
  created: (event) => ({
    id: event.contractId,
    owner: event.payload.owner,
    name: event.payload.name,
  }),
  archived: (event) => event.contractId,
});

await engine.start();

// Query projected data
const assets = store.getAll('Main:Asset');

Stores

| Store | Description | |-------|-------------| | InMemoryStore | Simple in-process Map-backed store for development and testing | | PlexusStore | Persists projections to a Plexus data layer collection |

Both stores implement the ProjectionStore interface, so you can swap them without changing projection logic.

License

Apache-2.0 -- see LICENSE for details.