title: What is `change` event in Angular 2
body: <p>What is <code>change</code> event in Angular 2? When is it dispatched and how can I use it?<br>
  I. e. what have I subscribed in following code via <code>(change)="update()"</code>?</p>
  
  <p><a href="http://plnkr.co/edit/mfoToOSLU6IU2zr0A8OB?p=preview" rel="noreferrer">http://plnkr.co/edit/mfoToOSLU6IU2zr0A8OB?p=preview</a></p>
  
  <pre><code>import {Component, View, Input, Output, EventEmitter, OnChanges} from '@angular/core'
  
  @Component({
    selector: 'inner-component',
    template: `
      &lt;label&gt;&lt;input type="checkbox" [(ngModel)]="data.isSelected"&gt; Selected&lt;/label&gt;
    `
  })
  export class InnerComponent {
    data = { isSelected: false };
  }
  
  @Component({
    selector: 'my-app',
    template: `
      &lt;p&gt;&lt;inner-component (change)="update()"&gt;&lt;/inner-component&gt;&lt;/p&gt;
      &lt;p&gt;The component was updated {{count}} times&lt;/p&gt;
    `,
    directives: [InnerComponent]
  })
  export class AppComponent {
    count = 0;
  
    update() {
      ++this.count;
    }
  }
  </code></pre>
  
  <p>PS: <a href="//ru.stackoverflow.com/q/542043/178988">Same question in Russian</a>.</p>