commit | 1c873a91a6774de0634e2cfebd9c723d278fd22a | [log] [tgz] |
---|---|---|
author | Sam Rawlins <sam.rawlins@gmail.com> | Thu Dec 21 16:26:54 2017 -0800 |
committer | GitHub <noreply@github.com> | Thu Dec 21 16:26:54 2017 -0800 |
tree | a06203939f8c83084107bfb7cdb071433c665bb6 | |
parent | 8c9596121f624b6b21cec9a7d45621bbdcd89535 [diff] | |
parent | 9054bc1a41ed4ee9702b15d1788b9bb05ec2d984 [diff] |
Merge pull request #43 from srawlins/generic-comments Fix generic comment syntax
Support for detecting and being notified when an object is mutated.
An observable is a way to be notified of a continuous stream of events over time.
Some suggested uses for this library:
You may want to look at the former TC39 proposal Observe.observe, which was deprecated.
There are two general ways to detect changes:
Observable.changes
and be notified when an object changesDiffer.diff
to determine changes between two objectsOperations on Lists:
import 'package:observable/observable.dart'; void main() { var changes; ObservableList<String> list = new ObservableList<String>.from(['a', 'b', 'c']); StreamSubscription sub = list.listChanges.listen((c) => changes = c); ListChangeRecord _delta( int index, { List removed: const [], int addedCount: 0, }) { return new ListChangeRecord( list, index, removed: removed, addedCount: addedCount, ); } list.insertAll(1, ['y', 'z']); // changes == [_delta(1, addedCount: 2)] }
Diffing two maps:
import 'package:observable/observable.dart'; void main() { final map1 = { 'key-a': 'value-a', 'key-b': 'value-b-old', }; final map2 = { 'key-a': 'value-a', 'key-b': 'value-b-new', }; var diffResult = diff(map1, map2); // [ new MapChangeRecord('key-b', 'value-b-old', 'value-b-new')] }
Diffing two sets:
import 'package:observable/observable.dart'; void main() { diff( new Set<String>.from(['a', 'b']), new Set<String>.from(['a']), ); // [ new SetChangeRecord.remove('b') ] }