title: How can I get my Angular2 DatePipe-formatted Date to update?
body: <p>Sample of the issue: <a href="http://plnkr.co/edit/7FeRoyyqDnjXpV9Q9Vpy?p=preview" rel="nofollow noreferrer">http://plnkr.co/edit/7FeRoyyqDnjXpV9Q9Vpy?p=preview</a></p>
  
  <pre><code>import {Component, NgModule} from '@angular/core'
  import {BrowserModule} from '@angular/platform-browser'
  
  @Component({
    selector: 'my-app',
    template: `
      &lt;div&gt;
        &lt;h2&gt;{{myDate}}&lt;/h2&gt; &lt;!-- THIS UPDATES AS EXPECTED --&gt;
        &lt;h2&gt;{{myDate | date: 'longDate'}}&lt;/h2&gt; &lt;!-- THIS DOES NOT --&gt;
        &lt;a (click)="prevMonth()" href="javascript:;"&gt;Previous Month&lt;/a&gt;
        &lt;a (click)="nextMonth()" href="javascript:;"&gt;Next Month&lt;/a&gt;
      &lt;/div&gt;
    `,
  })
  export class App {
    myDate: Date;
    constructor() {
      this.myDate = new Date();
    }
  
    nextMonth() {
      this.myDate.setMonth(this.myDate.getMonth() + 1);
    }
  
    prevMonth() {
      this.myDate.setMonth(this.myDate.getMonth() - 1);
    }
  }
  
  @NgModule({
    imports: [ BrowserModule ],
    declarations: [ App ],
    bootstrap: [ App ]
  })
  export class AppModule {}
  </code></pre>
  
  <p>When I pass my variable without using any pipes, it updates as expected.  But a DatePipe-formatted copy of that same variable does not update.  Does the pipe only update for observables?  Or can I use this with a standard Date type and expect it to update in realtime?</p>
  
  <p>I do not see anything in the DatePipe API that suggests this as the expected behavior, but I've narrowed it down to the point where only the DatePipe could be affecting the bahavior in this way.  <a href="https://angular.io/docs/ts/latest/api/common/index/DatePipe-pipe.html" rel="nofollow noreferrer">https://angular.io/docs/ts/latest/api/common/index/DatePipe-pipe.html</a></p>