react-native-audio-api/src/hooks/useSystemVolume.ts

react-native-audio-api provides system for controlling audio in React Native environment compatible with Web Audio API specification

import { useEffect, useState } from 'react';

import { AudioManager } from '../api';

export default function useSystemVolume() {
  const [volume, setVolume] = useState(0);

  useEffect(() => {
    AudioManager.observeVolumeChanges(true);
    const listener = AudioManager.addSystemEventListener(
      'volumeChange',
      (e) => {
        setVolume(parseFloat(e.value.toFixed(2)));
      }
    );

    return () => {
      listener?.remove();
      AudioManager.observeVolumeChanges(false);
    };
  }, []);

  return volume;
}