title: Angular2 ngModelChange previous value
body: <p>Is there a way to get the previous(last) value of a field on ngModelChange?
  What I have goes something like this</p>
  
  <p>HTML</p>
  
  <pre><code>&lt;input type="text" [(ngModel)]="text" (ngModelChange)="textChanged($event)"&gt;
  </code></pre>
  
  <p>Handler</p>
  
  <pre><code>private textChanged(event) {
      console.log('changed', this.text, event);
  }
  </code></pre>
  
  <p>What I get is</p>
  
  <pre><code>changed *newvalue* *newvalue*
  </code></pre>
  
  <p>Of course I can keep the older value using another variable, but is there a better way?</p>