How to trigger a change event on a textarea when setting the value via ngModel Binding - html

Question

I have a <textarea> within a template driven form of an Angular 7 project.
When editing an object, the form is prefilled with the current values. I want to automatically resize the <textarea> when the content has changed via the [(ngModel)]="property" binding by modifying the element-style.
area.style.overflow = 'hidden';
area.style.height = '0';
area.style.height = area.scrollHeight + 'px';
The code generally is working, but I cannot find a suitable event to trigger it.
Subscribing to the change event of the <textarea> is only working on keyboard input. Using (ngModelChange)="adjustTextAreaSize($event)" has the same behavior.
I tried to execute my resizing code at the end of the ngOnInit() function, but the actual html-control seems to not have any content yet at this point.
Does anyone have an idea which event could do the trick here?
Seemed a rather easy task in the beginning, but I'm breaking my had over this for over an hour now... can not be such a difficult task, can it?

Answer 1

Yes there is a very simple solution for this.
Wrap your textarea inside a form and try the code below:-
HTML
<form #form="ngForm">
<textarea>....</textarea>
</form>
TS
#ViewChild('form') ngForm: NgForm;
ngOnInit() {
this.subscription = this.ngForm.form.valueChanges.subscribe(resp =>
{
console.log(resp); // You get your event here
}
)
}
ngOnDestroy() {
this.subscription.unsubscribe();
}

Answer 2

trigger a change event on a textarea when setting the value via ngModel Binding
This will cause infinite triggering if you do so.
If you don't want to monitor the input model change in a more reactive way, a quicker solution (but a bit hacky) will be simply wrap your code inside setTimeout in ngOnInit() or ngAfterViewInit() where you mentioned it was not working.
setTimeout(() => {
updateSize();
});