@wrst/react-native

The phone-side companion bridge for wrst watch apps. Install it in your React Native app to talk to a paired wrst watch app (Apple Watch via WatchConnectivity, Wear OS via the Wearable Data Layer). It's the counterpart to the watch's Companion API (from the wrst package) - both speak the same wire contract.

npm install @wrst/react-native
cd ios && pod install   # iOS only

Autolinked - no manual native registration. The native module has no effect in Expo Go or on web (there's no native host); use a dev/prebuild build.

Usage

import { Companion } from "@wrst/react-native";

// Is the watch app reachable + installed right now?
const { available, reason } = await Companion.getStatus();

// React to link changes (e.g. update UI).
const sub = Companion.onStatusChange(({ available, reason }) => {
  /* ... */
});

// Send a message to the watch (received there via Companion.onMessage).
await Companion.sendMessage({ type: "ping", at: Date.now() });

// Receive messages the watch sent (e.g. a request to fetch on its behalf).
const msgSub = Companion.onMessage((msg) => {
  /* reply via sendMessage */
});

// Clean up.
sub.remove();
msgSub.remove();

reason ("no-device" | "app-not-installed" | "unreachable" | null) is for UI text only - branch behavior on available.

Wire contract (shared with the watch)

• Capability string wrst_companion - advertised by both sides; the Wear OS Data Layer uses it for discovery (bundled res/values/wear.xml).
• Message path /wrst (Android) / dict key "wrst" (iOS).
• Payloads are JSON strings (sendMessage stringifies; receivers JSON.parse).

See CONTRACT.md in the wrst repo.

Scope

This package is just the phone-side bridge. Scaffolding the watch app into your RN project (the apple-watch/ + wear-os/ folders, prebuilt xcframework/AAR, the Expo config plugin) is handled by wrst init --companion - see the repo.