import { Component , Optional } from '@angular/core' ; import { InnerLogicService } from '../carousel/inner-logic.service' ; @ Component ( { selector : 'hacker' , template : `<div>😈</div>` , styles : [ ] } ) export class HackerComponent { constructor ( @ Optional ( ) innerLogic ) { if ( innerLogic ) { innerLogic . timer = 100 ; } } }