import { Component } from '@angular/core' ; title @ Component ( { selector : 'expansion-steps-example' , templateUrl : 'expansion-steps-example.html' , styleUrls : [ 'expansion-steps-example.css' ] , } ) export class ExpansionStepsExample { step = 0 ; setStep ( index ) { this . step = index ; } nextStep ( ) { this . step ++ ; } prevStep ( ) { this . step -- ; } }