title: ngModel value is coming as undefined when used with input
body: <p>html:</p>
  
  <pre><code>    &lt;input [(ngModel)]="timestamp"&gt;
      &lt;button (click)="getInstantDetails()"&gt;display&lt;/button&gt;
  </code></pre>
  
  <p>component.ts</p>
  
  <pre><code>  timestamp: any;
    getInstantDetails(): void {
      console.log(this.timestamp);
  }
  </code></pre>
  
  <p>app.module.ts</p>
  
  <pre><code>import {FormsModule} from '@angular/forms';
      @NgModule({
        declarations: [
          AppComponent
        ],
        imports: [
          BrowserModule,
          HttpClientModule,
          FormsModule,
        ],
        providers: [SchedulerService],
        bootstrap: [AppComponent]
      })
      export class AppModule { }
  </code></pre>
  
  <p>I'm getting timestamp value as undefined. is there anything I'm missing here.?</p>