Angular 2 ngModelChange old value

Question

Can someone please tell me what is the best practice for comparing ngModel old and new value?

In angular 1:

$scope.$watch(\'someProperty\', funciton(         


        

Answer 1

This might work

(ngModelChange)="onModelChange(oldVal, $event); oldVal = $event;"

or

(ngModelChange)="onModelChange($event)"

oldValue:string;
onModelChange(event) {
  if(this.oldValue != event) {
    ...
  }
  this.oldValue = event;
}