Parent-Component

eventsSubject: Subject = new Subject();

emitEventToChild() {
  this.eventsSubject.next();
}


Parent-HTML

 


Child-Component

private eventsSubscription: Subscription;

@Input() events: Observable;

ngOnInit(){
  this.eventsSubscription = this.events.subscribe(() => doSomething());
}

ngOnDestroy() {
  this.eventsSubscription.unsubscribe();
}