intro-to-flutter-27.dart

class SharedPrefTokenRepository implements TokenRepository {
  @override
  Future<void> save(String token) async =>
      (await SharedPreferences.getInstance()).setString(_keyToken, token);

  @override
  Future<String> load() async =>
      (await SharedPreferences.getInstance()).getString(_keyToken);

  static const String _keyToken = 'token';
}