78 lines
1.9 KiB
Dart
78 lines
1.9 KiB
Dart
// #docregion
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import 'package:angular2/angular2.dart';
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import 'logger_service.dart';
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import 'spy_directive.dart';
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@Component(
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selector: 'my-counter',
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template: '''
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<div class="counter">
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Counter = {{counter}}
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<h5>-- Counter Change Log --</h5>
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<div *ngFor="#chg of changeLog" mySpy>{{chg}}</div>
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</div>
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''',
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styles: const [
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'.counter {background: LightYellow; padding: 8px; margin-top: 8px}'
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],
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directives: const [Spy])
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class MyCounter implements OnChanges {
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@Input() num counter;
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List<String> changeLog = [];
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ngOnChanges(Map<String, SimpleChange> changes) {
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// Empty the changeLog whenever counter goes to zero
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// hint: this is a way to respond programmatically to external value changes.
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if (this.counter == 0) {
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changeLog.clear();
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}
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// A change to `counter` is the only change we care about
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SimpleChange prop = changes['counter'];
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var prev = prop.isFirstChange() ? "{}" : prop.previousValue;
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changeLog.add(
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'counter: currentValue = ${prop.currentValue}, previousValue = $prev');
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}
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}
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@Component(
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selector: 'counter-parent',
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template: '''
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<div class="parent">
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<h2>Counter Spy</h2>
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<button (click)="updateCounter()">Update counter</button>
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<button (click)="reset()">Reset Counter</button>
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<my-counter [counter]="value"></my-counter>
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<h4>-- Spy Lifecycle Hook Log --</h4>
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<div *ngFor="#msg of spyLog">{{msg}}</div>
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</div>
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''',
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styles: const [
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'.parent {background: gold; padding: 10px; margin:100px 8px;}'
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],
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directives: const [MyCounter],
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providers: const [LoggerService])
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class CounterParentComponent {
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num value;
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List<String> spyLog = [];
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LoggerService _logger;
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CounterParentComponent(this._logger) {
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spyLog = _logger.logs;
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reset();
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}
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updateCounter() => value += 1;
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reset() {
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_logger.log('-- reset --');
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value = 0;
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}
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}
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