LeCodesdocs

Service

Raw access to a host-registered headless service — the UI-less sibling of NativeView. A service is native code the host registered under a name (engine.registerService("app.battery") { params, channel in … } on iOS); the app talks to it over a JSON call/event session. First-party services ship with typed wrappers (Geolocation, Push) — Service is for everything else: native code you wrote in your own app shell and third-party plugins that don't ship a wrapper library.

Host-optional, like every plugin: the web editor registers no services, so always gate on Service.isSupported(name).

TypeScript
if (Service.isSupported("app.battery")) {
  const battery = Service("app.battery")
  battery.on("change", data => { levelText.text = data.level + "%" })
  const { level, charging } = await battery.call("level")
}

API

  • Service(name, params?) — a client for the named service. The host session opens lazily on the first call(); params are handed to the host factory at that moment.
  • Service.isSupported(name) — whether this host registered a factory under name.
  • .call(method, ...args) — invoke a method; arguments and the result are JSON-serialized. Rejects when the host has no such service, or the native side reports an error.
  • .on(event, cb) / .off(event, cb) — subscribe to events the service emits while a session is open. Payloads arrive JSON-decoded.
  • .close() — close the host session (the native side stops whatever it was doing). Listeners stay registered; a later call() opens a fresh session that delivers to them again.

Naming

First-party services own bare names (geolocation, push). Name app-local services app.* (app.battery) and third-party plugin services with a vendor prefix (acme.bluetooth) — bare names are reserved for the SDK.

For a one-off synchronous value (no events, no async), the host-side engine.registerCallback("native.thing") { … } injecting a plain global can be simpler than a service — see the app-shell docs. Reach for Service as soon as you need events, async work, or session state.

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