react-navigation/src/PlatformHelpers.native.js

Routing and navigation for your React Native apps

import {
  BackAndroid as DeprecatedBackAndroid,
  BackHandler as ModernBackHandler,
  MaskedViewIOS,
} from 'react-native';

const BackHandler = ModernBackHandler || DeprecatedBackAndroid;

export { BackHandler, MaskedViewIOS };