# @mosaicstack/telemetry-client

TypeScript/JavaScript client SDK for Mosaic Stack Telemetry. Zero runtime dependencies.

## Commands

```bash
npm install          # Install dependencies
npm run typecheck    # Type check
npm run lint         # Lint
npm run format:check # Format check
npm test             # Run tests
npm run test:coverage # Tests with coverage (85% threshold)
npm run build        # Build to dist/
```

## Architecture

- `client.ts` — TelemetryClient (main public API, setInterval-based background flush)
- `queue.ts` — EventQueue (bounded FIFO array)
- `submitter.ts` — BatchSubmitter (native fetch, exponential backoff, Retry-After)
- `prediction-cache.ts` — PredictionCache (Map + TTL)
- `event-builder.ts` — EventBuilder (auto-generates event_id, timestamp)
- `types/` — Standalone type definitions matching server API schema v1.0

## Key Patterns

- `track()` never throws — catches everything, routes to `onError` callback
- Zero runtime deps: uses native `fetch` (Node 18+), `crypto.randomUUID()`, `setInterval`
- All types are standalone — no dependency on the telemetry server package