using the ng change in angular 2 using ng model variable

Question

How can I use the ng-change event in angular 2? Whenever the ng-model variable is changed, a function has to be called.

[(ngModel)]="variable" ngchange=variable; 

Answer 1

You could use the ngModelChange event:

[(ngModel)]="variable" (ngModelChange)="doSomething($event)" 

Edit

According to your comment, I think that you should use form control with a custom validator.

Here is a sample:

@Component({   (...)   template: `     <input [(ngModel)]="variable" [ngFormControl]="ctrl"/>   ` }) export class SomeComponent {   constructor() {     this.ctrl = new Control('', (control) => {       // validate the value     });      this.ctrl.valueChanges.subscribe((value) => {       // called when the value is updated     });    } } 

See this article for more details:

• http://restlet.com/blog/2016/02/11/implementing-angular2-forms-beyond-basics-part-1/