import { Directive , Host , OnInit } from '@angular/core' ; import { WizardStep } from '../util/wizard-step.interface' ; author Marc Arndt
  @ Directive ( { selector : '[optionalStep]' , } ) export class OptionalStepDirective implements OnInit { param wizardStep constructor ( @ Host ( ) private wizardStep ) { } /**
     * Initialization work
     */ ngOnInit ( ) { this . wizardStep . optional = true ; } }