fix(useBattery): prevent state update and memory leak on unmount

  Add mounted flag to handle cleanup when component unmounts before
  getBattery() promise resolves. This prevents setState calls on
  unmounted components and avoids registering event listeners that
  would never be cleaned up.

Author: samithahansaka

src/useBattery/index.ts

@@ -96,15 +96,20 @@ export function useBattery(): UseBatteryState {
 		}
 
 		let battery: BatteryManager | null = null;
+		let mounted = true;
 
 		const handleChange = () => {
-			if (battery) {
+			if (battery && mounted) {
 				setState(getBatteryState(battery));
 			}
 		};
 
 		// eslint-disable-next-line @typescript-eslint/no-floating-promises,promise/catch-or-return,promise/prefer-await-to-then,promise/always-return
 		nav.getBattery().then((b) => {
+			if (!mounted) {
+				return;
+			}
+
 			battery = b;
 			setState(getBatteryState(battery));
 
@@ -115,6 +120,7 @@ export function useBattery(): UseBatteryState {
 		});
 
 		return () => {
+			mounted = false;
 			if (battery) {
 				off(battery, 'chargingchange', handleChange);
 				off(battery, 'chargingtimechange', handleChange);