@peloruslabs/station-core

Host-agnostic marine engines for the Aelos boat brain. The anchor-watch engine is the first engine to live here: it decides when a vessel has dragged anchor, and it keeps the swing trail that gets drawn on screen.

The package is pure TypeScript — no Node and no React Native dependencies. zod is the single runtime dependency, declared as a peer dependency so the host application owns the version. The same code therefore runs inside a mobile app, on a server, or on a small onboard computer such as a Signal K installation.

Pre-release and unpublished. Nothing here is on npm yet, and the public API is expected to change without notice. See docs/api-pass-notes.md in the repo root for the API cleanup that is deferred until the first publish.

Quickstart

npm install @peloruslabs/station-core zod

import { arm, onFix, onTick, watchConfigSchema, type Fix } from '@peloruslabs/station-core';

// Drop the hook: parse the config so the tuning defaults get filled in.
const config = watchConfigSchema.parse({
  anchor: { lat: 47.6, lon: -122.3 },
  radiusM: 40,
});

let state = arm(config, Date.now());

// Feed each GPS fix as it arrives; the returned state carries the phase.
const fix: Fix = { point: { lat: 47.6004, lon: -122.3 }, accuracyM: 5, atMs: Date.now() };
state = onFix(state, fix, fix.atMs);

// Tick on a timer too, so a feed that goes quiet can raise 'gps-degraded'.
state = onTick(state, Date.now());

if (state.phase === 'alarm') {
  // …wake the skipper.
}

The engine is pure and synchronous: every function takes the current state plus the current time and returns the next state — the host owns the clock, the GPS feed, and the alarm. Distances are metres, angles are degrees, and times are epoch milliseconds throughout; the engine never converts for display.

Docs and license

See the repo root for full docs, the monorepo layout, and the development gate. Apache-2.0. Copyright 2026 Pelorus Labs LLC.