The platform-agnostic engine behind the Pulse SDKs. It implements the Pulse wire protocol — the persistent ordered queue, batching, idempotent retry, and identity lifecycle — with no DOM and no React Native APIs. Everything platform-specific (storage, transport, clock) is injected.

Most apps should install @pulse-circle/web or @pulse-circle/react-native instead. Use @pulse-circle/core directly only when porting Pulse to a new JavaScript runtime.

Install

npm install @pulse-circle/core

What it does

PulseClient owns the whole protocol state machine. You give it four seams:

import { PulseClient, DEFAULT_ENDPOINT, SDK_VERSION } from '@pulse-circle/core';

const client = new PulseClient({
  apiKey: 'pk_...',
  defaults: {
    endpoint: DEFAULT_ENDPOINT,
    flushAt: 20,
    flushIntervalMs: 30_000,
    maxQueueEvents: 5_000,
    debug: false,
  },
  sdk: { name: 'pulse-myplatform', version: SDK_VERSION },
  transport,        // PulseTransport: how requests go out
  clock,            // PulseClock: now() + timer scheduling
  keyValueStorage,  // PulseKeyValueStorage: identity persistence
  queueStorage,     // PulseQueueStorage: the durable event queue
});

client.track('event', { key: 'value' });
client.identify('user_42');
client.reset();
client.flush();

Because time and I/O are injected, the client is fully deterministic under test — no real timers, no real network.

Testing utilities

@pulse-circle/core/testing ships the test doubles and the conformance fixture runner used by every platform:

import {
  MockTransport,
  VirtualClock,
  InMemoryKeyValueStorage,
  InMemoryQueueStorage,
  runFixture,
} from '@pulse-circle/core/testing';

runFixture(fixture, createClient) drives a client through a protocol scenario (see FIXTURES.md) and asserts the exact HTTP requests it produces. Porting Pulse to a new runtime means: implement the four seams, then pass every fixture.