awaforge

battery

Apache-2.0Release 1L3

Wrapper around the Battery Status API (navigator.getBattery()).

Module battery | Source packages/front/fw/src/dom/sensors/battery.js | Deps none | Worker-safe no

Deprecation note: The Battery Status API is deprecated in Firefox and Safari for privacy reasons (fingerprinting). It remains available in Chrome/Edge but may disappear. Use isSupported() before any usage, and do not base critical features on it.

Resolve

const battery = runtime.resolve('battery');
// Returns: { isSupported, current, watch }

API

Method Signature Returns
isSupported () => boolean 'getBattery' in navigator
current () => Promise<BatteryInfo> Current state or throw
watch (callback) => stop stop fn

Type BatteryInfo

{
    level: number,            // 0..1 (0% to 100%)
    charging: boolean,
    chargingTime: number,     // seconds until 100%; Infinity if not measurable
    dischargingTime: number,  // seconds until 0%; Infinity if charging
}

Examples

const battery = runtime.resolve('battery');

if (battery.isSupported()) {
    const info = await battery.current();
    console.log(`${Math.round(info.level * 100)}% — ${info.charging ? 'charging' : 'on battery'}`);
}

// Real-time observation
const stop = battery.watch(info => {
    if (info.level < 0.1 && !info.charging) alert('Low battery!');
});
// stop() when done

Notes

  • isSupported() must be checked — most modern browsers have removed or frozen this API.
  • watch() is async internally (getBattery() is a Promise). The initial callback is called as soon as the Promise resolves.
  • Observed events: levelchange, chargingchange, chargingtimechange, dischargingtimechange.

See also