commit | b9de72560f975031032d029b9bf8c7e2408d0138 | [log] [tgz] |
---|---|---|
author | Sam Rawlins <sam.rawlins@gmail.com> | Wed Dec 27 10:20:03 2017 -0800 |
committer | GitHub <noreply@github.com> | Wed Dec 27 10:20:03 2017 -0800 |
tree | f612ae751ce02e10f90e49f72e945555cd0c61d3 | |
parent | 1c873a91a6774de0634e2cfebd9c723d278fd22a [diff] | |
parent | c254d29a71c9b474a472d6ec40f26170d4ad144a [diff] |
Merge pull request #45 from srawlins/bump-quiver Expand the quiver version constraints
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') ] }