Angular2 ngModelChange previous value

What you can do is,

DEMO : http://plnkr.co/edit/RXJ4D0YJrgebzYcEiaSR?p=preview

<input type="text" 
       [ngModel]="text"                      //<<<###changed [(ngModel)]="text" to [ngModel]="text"
       (ngModelChange)="textChanged($event)"> 

private textChanged(event) {        
    console.log('changed', this.text, event);
    this.text=event;                          //<<<###added 
}