How to update deeply nested List<Object>?

[pqt-dev]

Assume I have 3 freezed classes: (skip syntax error please).

@freezed
class Region {
  final String id;
  final String name;
  final List<County> counties;

  const Region({
    required this.id,
    required this.name,
    required this.counties,
  });
}

@freezed
class County {
  final String id;
  final String name;
  final List<District> districts;

  const County({
    required this.id,
    required this.name,
    required this.districts,
  });
}

@freezed
class District {
  final String id;
  final String name;

  const District({
    required this.id,
    required this.name,
  });
}

final regions = <Region>[]; 
regions.add(
  const Region(
    id: '1',
    name: 'North East England',
    counties: [
      County(
        id: '1',
        name: 'County Durham',
        districts: [
          District(id: '1', name: 'Durham'),
          District(id: '2', name: 'Chester-le-Street'),
        ],
      ),
      County(
        id: '2',
        name: 'Northumberland',
        districts: [
          District(id: '1', name: 'Alnwick'),
          District(id: '2', name: 'Blyth'),
        ],
      ),
    ],
  ),
);

Currently, if I would like to update the District with id=2, I do:

regions.map(
      (region) {
        return region.couties.map((county) {
          return county.districts.map((district) {
            if (district.id == '2') {
              return district.copyWith(
                name: 'New district',
              );
            }else{
              return district.copyWith();
            }
          }).toList();
        }).toList();
      },
    );

Is this the best way to update adeeply nested object in List?
Is there a shorter way to implement this?
@rrousselGit Sorry for mention.
Thank you so much!

[ChunhThanhDe]

Hi @phamquoctrongdev,

you can optimize the way you update District by this way:

regions = regions.map((region) => region.copyWith(
  counties: region.counties.map((county) => county.copyWith(
    districts: county.districts.map((district) => 
      district.id == '2' ? district.copyWith(name: 'New district') : district
    ).toList(),
  )).toList(),
)).toList();

[ChunhThanhDe]

easier to read by arrow functions xD

[pqt-dev]

Thanks for your response.
But it looks like still verbose?
Anyway thanks.