Changes watcher

Overview

Execute code upon value change

Example

import {WatchDirective} from "./watch/watch.directive";

bootstrap(AppComponent, [
    {provide: ng.PLATFORM_DIRECTIVES, useValue: WatchDirective, multi: true}
]);
<h1>Watcher</h1>
<input [(ngModel)]="watchData" value="Write here" [a2Watch]="watchData"
    (a2Change)="changeEvent = $event"> <br>
changeEvent: {{changeEvent | json}}