import { Component , Input , OnChanges , SimpleChanges } from '@angular/core' ; @ Component ( { selector : 'app-dummy-content' , templateUrl : './dummy-content.component.html' , } ) export class DummyContentComponent implements OnChanges { @ Input ( ) length = 1 ; public array = [ 0 ] ; constructor ( ) { } ngOnChanges ( changes ) { this . array = Array . from ( Array ( this . length ) , ( e , i ) => i ) ; } }