Here's the situation:
parent.component.html
<form #someForm >
<input type="text" name="title" [(ngModel)]="parentVar" />
<child-component />
<input type="submit" [disabled]="someForm.form.pristine" />
</form>
child.component.html
<div>
<input type="number" name="foo" [(ngModel)]="childVar" />
</div>
When I change value of 'title' input the submit button gets enabled, but when change the value of 'foo' input nothing happens. How can I render the form dirty from the child component?