ORSet<T>.fromMap constructor

ORSet<T>.fromMap(Map<String, dynamic> map, T decoder(dynamic))

Implementation

factory ORSet.fromMap(Map<String, dynamic> map, T Function(dynamic) decoder) {
  // Format 2 stores entries as {'e': encodedElement, 't': [tags]} so the
  // element round-trips through [decoder] faithfully. The legacy format
  // stringified elements into JSON map KEYS — `toString()` has no inverse,
  // so any non-String element type either crashed the decoder or collided
  // distinct elements into one key (merging their tag sets).
  if (map['format'] == 2) {
    Map<T, Set<String>> parse(String key) => {
          for (final raw in (map[key] as List? ?? const [])) decoder((raw as Map)['e']): ((raw['t'] as List?) ?? const []).cast<String>().toSet(),
        };
    return ORSet(addSet: parse('add'), removeSet: parse('remove'));
  }

  final addMap = <T, Set<String>>{};
  (map['add'] as Map<String, dynamic>?)?.forEach((k, v) {
    addMap[decoder(k)] = (v as List).cast<String>().toSet();
  });

  final removeMap = <T, Set<String>>{};
  (map['remove'] as Map<String, dynamic>?)?.forEach((k, v) {
    removeMap[decoder(k)] = (v as List).cast<String>().toSet();
  });

  return ORSet(addSet: addMap, removeSet: removeMap);
}