Trigger OnChanges by changing a property on a data-related object

Question

How can I get ngOnChanges () to fire if a property on one of the data-related objects changes, instead of setting the property to a new object.

// component
@Input() myObj: ObjType;
// component code...

It does not cause a change

// outside component
dataBoundObj.width = 1000;

It does

dataBoundObj = new ObjType();

Answer 1

Angular does not detect changes when the object is mutated. However, when checking the current component, it starts ngDoCheck. Thus, you can perform the check yourself and run ngOnChangesfrom there:

ngDoCheck() {
   if (this.o.width !== this.oldWidth) {
      this.ngOnChanges();
   }
}