deepCopy method

Map deepCopy()

https://stackoverflow.com/questions/64594543/how-to-deep-copy-nested-list-in-dart

so called shallow copy

Implementation

Map deepCopy() {
  var newMap = {};

  forEach((key, value) {
    if (value is Map) {
      newMap.addAll({key: value.deepCopy()});
    } else if (value is List) {
      newMap.addAll({key: value.deepCopy()});
    } else if (value is Set) {
      newMap.addAll({key: value.deepCopy()});
    } else {
      newMap.addAll({key: value});
    }
  });

  return newMap;
}