m3_lightmeter/lib/data/models/metering_screen_layout_config.dart

enum MeteringScreenLayoutFeature { extremeExposurePairs, filmPicker, histogram }

typedef MeteringScreenLayoutConfig = Map<MeteringScreenLayoutFeature, bool>;

extension MeteringScreenLayoutConfigJson on MeteringScreenLayoutConfig {
 static MeteringScreenLayoutConfig fromJson(Map<String, dynamic> data) =>
      <MeteringScreenLayoutFeature, bool>{
        for (final f in MeteringScreenLayoutFeature.values)
          f: data[f.index.toString()] as bool? ?? true
      };

  Map<String, dynamic> toJson() => map((key, value) => MapEntry(key.index.toString(), value));
}