I have ParentComponent and a ChildComponent, and I need to pass the ngModel in ParentComponent to ChildComponent.
// the below is in ParentComponent template
<child-component [(ngModel)]="valueInParentComponent"></child-component>
how can I get the value of ngModel in ChildComponent and manipulate it?
You need to implement ControlValueAccessor
in the child class.
It's what defines your component as "having a value" that can be bound to using the angular way.
Read more about it here: http://blog.thoughtram.io/angular/2016/07/27/custom-form-controls-in-angular-2.html