# javascript – (change) vs (ngModelChange) in angular

## The Question :

373 people think this question is useful

Angular 1 does not accept onchange() event, it’s only accepts ng-change() event.

Angular 2, on the other hand, accepts both (change) and (ngModelChange) events, which both seems to be doing the same thing.

What’s the difference?

which one is best for performance?

ngModelChange:

<input type="text" pInputText class="ui-widget ui-text"
(ngModelChange)="clearFilter()" placeholder="Find"/>



vs change:

<input type="text" pInputText class="ui-widget ui-text"
(change)="clearFilter()" placeholder="Find"/>


• I don’t want to compare those. I just want to know which one is best for performance ?
• Yeah there is no comparison . If you are using ngModel you can use the later otherwise the first one . Its always preferred to avoid ngModel as that’s two way data binding , hence bad for performance
• Edited to put emphasis on “what’s the difference” and “which is more performant” to remove subjectivity & voted to reopen.
• In Angular 7, the (ngModelChange)=”eventHandler()” will fire BEFORE the value bound to [(ngModel)]=”value” is changed while the (change)=”eventHandler()” will fire AFTER the value bound to [(ngModel)]=”value” is changed.
• By the way, the (change) event is fired only when the focus leaves the input. If you want an event fired after each key-press, you can use the (input) event.

555 people think this answer is useful

(change) event bound to classical input change event.

https://developer.mozilla.org/en-US/docs/Web/Events/change

You can use (change) event even if you don’t have a model at your input as

<input (change)="somethingChanged()">



(ngModelChange) is the @Output of ngModel directive. It fires when the model changes. You cannot use this event without ngModel directive.

https://github.com/angular/angular/blob/master/packages/forms/src/directives/ng_model.ts#L124

As you discover more in the source code, (ngModelChange) emits the new value.

https://github.com/angular/angular/blob/master/packages/forms/src/directives/ng_model.ts#L169

So it means you have ability of such usage:

<input (ngModelChange)="modelChanged($event)">  modelChanged(newObj) { // do something with new value }  Basically, it seems like there is no big difference between two, but ngModel events gains the power when you use [ngValue].  <select [(ngModel)]="data" (ngModelChange)="dataChanged($event)" name="data">
<option *ngFor="let currentData of allData" [ngValue]="currentData">
{{data.name}}
</option>
</select>


dataChanged(newObj) {
// here comes the object as parameter
}



assume you try the same thing without “ngModel things”

<select (change)="changed($event)"> <option *ngFor="let currentData of allData" [value]="currentData.id"> {{data.name}} </option> </select>  changed(e){ // event comes as parameter, you'll have to find selectedData manually // by using e.target.data }  ## The Answer 2 102 people think this answer is useful In Angular 7, the (ngModelChange)="eventHandler()" will fire before the value bound to [(ngModel)]="value" is changed while the (change)="eventHandler()" will fire after the value bound to [(ngModel)]="value" is changed. ## The Answer 3 24 people think this answer is useful As I have found and wrote in another topic – this applies to angular < 7 (not sure how it is in 7+) Just for the future we need to observe that [(ngModel)]="hero.name" is just a short-cut that can be de-sugared to: [ngModel]="hero.name" (ngModelChange)="hero.name =$event".

So if we de-sugar code we would end up with:

<select (ngModelChange)="onModelChange()" [ngModel]="hero.name" (ngModelChange)="hero.name = $event"> or <[ngModel]="hero.name" (ngModelChange)="hero.name =$event" select (ngModelChange)="onModelChange()">

If you inspect the above code you will notice that we end up with 2 ngModelChange events and those need to be executed in some order.

Summing up: If you place ngModelChange before ngModel, you get the \$event as the new value, but your model object still holds previous value. If you place it after ngModel, the model will already have the new value.

SOURCE

1 – (change) is bound to the HTML onchange event. The documentation about HTML onchange says the following :
Execute a JavaScript when a user changes the selected option of a <select> element
2 – As stated before, (ngModelChange) is bound to the model variable binded to your input.
• (change) triggers when the user changes the input
• (ngModelChange) triggers when the model changes, whether it’s consecutive to a user action or not