Collection modification changes a collection by adding, removing, or replacing an object. Angular does not automatically invoke an iterating directive’s ngOnChanges for these changes, so the directive must detect them separately. section 15.3.4
Implementing ngDoCheck lets a directive inspect changes during application change detection, but it runs whenever Angular detects a change anywhere. Rebuilding every embedded view is therefore simple but potentially inefficient. section 15.3.4
Deleting a product
A component can call model.deleteProduct(item.id) from a row button. The iterator directive then detects the removed collection item and removes its associated view.
