如何知道当前页面是来自正向还是来自后向，Ionic2

import { Component } from '@angular/core';
import { NavController } from 'ionic-angular';

@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {

  constructor(public navCtrl: NavController) {}

  goToPage() {
    // 获取当前页面的URL
    const currentUrl = this.navCtrl.getActive().component.name;

    // 导航到目标页面
    this.navCtrl.push(NextPage);

    // 获取目标页面的URL
    const targetUrl = NextPage.name;

    // 判断导航方向
    if (currentUrl === targetUrl) {
      console.log('来自正向导航');
    } else {
      console.log('来自后向导航');
    }
  }

}