import { Injectable } from '@angular/core' ; import { of as observableOf , Observable } from 'rxjs' ; import { TrafficChartData } from '../data/traffic-chart' ; @ Injectable ( ) export class TrafficChartService extends TrafficChartData { private data : number [ ] = [ 300 , 520 , 435 , 530 , 730 , 620 , 660 , 860 , ] ; getTrafficChartData ( ) { return observableOf ( this . data ) ; } }