0.20.4+2
Fix some types where DDC expects more strictness: (#44)

Fix some types where DDC expects more strictness:

* `ChangeRecord.NONE` creates a `List<ChangeRecord>`, while the call sites
  expect a `List<ListChangeRecord>` or `List<MapChangeRecord>`, respectively.
8 files changed
tree: 1e922774e36b293b77fd1b8b9da2041d4278a34d
  1. lib/
  2. test/
  3. .analysis_options
  4. .gitignore
  5. .travis.yml
  6. AUTHORS
  7. CHANGELOG.md
  8. CONTRIBUTING.md
  9. LICENSE
  10. PATENTS
  11. README.md
  12. pubspec.yaml
README.md

Build Status

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:

  • Observe objects for changes, and log when a change occurs
  • Optimize for observable collections in your own APIs and libraries instead of diffing
  • Implement simple data-binding by listening to streams

You may want to look at the former TC39 proposal Observe.observe, which was deprecated.

Usage

There are two general ways to detect changes:

  • Listen to Observable.changes and be notified when an object changes
  • Use Differ.diff to determine changes between two objects

Examples

Operations 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') ]
}