blob: 31d93cb352dbdd89cb88f70a051d4a799ce9f5bf [file] [log] [blame]
// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
part of observable.src.differs;
/// Determines differences between two maps, returning [SetChangeRecord]s.
/// While [SetChangeRecord] has more information and can be replayed they carry
/// a more significant cost to calculate and create and should only be used when
/// the details in the record will actually be used.
/// See also [EqualityDiffer] for a simpler comparison.
class SetDiffer<E> implements Differ<Set<E>> {
const SetDiffer();
List<SetChangeRecord<E>> diff(Set<E> oldValue, Set<E> newValue) {
if (identical(oldValue, newValue)) {
return ChangeRecord.NONE;
final changes = <SetChangeRecord<E>>[];
for (final added in newValue.difference(oldValue)) {
changes.add(new SetChangeRecord<E>.add(added));
for (final removed in oldValue.difference(newValue)) {
changes.add(new SetChangeRecord<E>.remove(removed));
return changes;