The ngOnChanges
lifecycle hook is executed when any of the components data-bound input
properties are changed. Let us see
how this works with a simple example.
We have a parent component which has a nested child component. The parent
component has a property “message”, the component also has a button on click of
which we change the text of the message property in the button’s click handler.
We embed a child component and pass the message as an @Input property to the child component. When we click the button in
the parent component the message property changes and hence the value passed in
the @Input property will also change, this should trigger the ngOnChanges
lifecycle hook in the child component.
