问如果我们在Primeng orderlist中使用drag n drop对元素重新排序，如何获得新的修改后的索引

EN

<div class=image>
<app-header></app-header>
<p-orderList [value]="thumbnail" header="Hotel View" [listStyle]="{'height':'400px'}" filterBy="tag"
 filterPlaceholder="Filter by Tag" dragdrop="true" onReorder="onReorderNodes($event)">
    <ng-template let-thumbnail pTemplate="item">
        <div class="ui-helper-clearfix">
            <img [src]="'data:image/jpg;base64,'+thumbnail.image |secure| async" width="100">
            <div  style="font-size:20px;float:right;margin:15px 5px 0 0">
                <b>Tag</b>-Tag1,tag2,tag....
                <b>Year</b>-2010
            </div>
        </div>
        {{$event}}
    </ng-template>
</p-orderList>
</div>

import { Component, OnInit, Input } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Router, ActivatedRoute } from '@angular/router';
import { NgxSpinnerService } from "ngx-spinner"; 
@Component({
  selector: 'app-image',
  templateUrl: './image.component.html',
  styleUrls: ['./image.component.css']
})   

export class ImageComponent implements OnInit {


  thumbnail: any;
  
  constructor(private http: HttpClient, private activatedRoute: ActivatedRoute,
    private SpinnerService: NgxSpinnerService) { }

  ngOnInit(): void {
    let imgAssetId = this.activatedRoute.snapshot.paramMap.get('assetId');
    if (imgAssetId != null) {
      this.getHotelAllImages(imgAssetId);
    }
    else {
      alert("No images present for asset " + imgAssetId)
    }
  }

  getHotelAllImages(assetId: string) {
    this.SpinnerService.show();  
    console.log("Asset ID: " + assetId)
    this.http.get<any>(this.url2 + Number(assetId))
      .subscribe(data => {
        this.thumbnail = data;
        this.SpinnerService.hide(); 
        if (this.thumbnail == null) {
          alert("No images present for Asset Id:" + assetId);
        }
        console.log("output " + this.thumbnail)
      })
  }    
}