import { ViewportScroller } from '@angular/common' ; import { Injectable } from '@angular/core' ; @ Injectable ( ) export class ServerViewportScroller extends ViewportScroller { getScrollPosition ( ) { return [ 0 , 0 ] ; } scrollToAnchor ( anchor ) { } scrollToPosition ( position ) { } setHistoryScrollRestoration ( scrollRestoration ) { } setOffset ( offset ) { } }