import { Component, OnInit } from '@angular/core'; import { Customer } from 'app/customer.model'; import { DataService } from 'app/data.service'; import { LoggerService } from 'app/logger.service'; @Component({ selector: 'app-customer-list', templateUrl: './customer-list.component.html', styleUrls: ['./customer-list.component.css'] }) export class CustomerListComponent implements OnInit { customers: Customer[]; customer: Customer; constructor(private dataService: DataService, private loggerService: LoggerService) { } ngOnInit() { this.loggerService.log('Getting customers'); this.customers = this.dataService.getCustomers(); } shift(increment: number) { let ix = this.customers.findIndex(c => c === this.customer) + increment; ix = Math.min(this.customers.length - 1, Math.max(0, ix)); this.customer = this.customers[ix]; } }