| // Copyright (c) 2021, 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. |
| |
| import 'package:collection/collection.dart'; |
| |
| /// Like [mergeMaps], but assumes both maps are unmodifiable and so avoids |
| /// creating a new map unnecessarily. |
| /// |
| /// The return value *may or may not* be unmodifiable. |
| Map<K, V> mergeUnmodifiableMaps<K, V>(Map<K, V> map1, Map<K, V> map2, |
| {V Function(V, V)? value}) { |
| if (map1.isEmpty) return map2; |
| if (map2.isEmpty) return map1; |
| return mergeMaps(map1, map2, value: value); |
| } |
