未捕获的TypeError：map.downloadExport不是函数（angular 2 typescript）

Question

我在我的打字稿类中遇到以下错误，无法理解原因。我正在做的就是尝试调用一个传递令牌的辅助函数。

错误：发布错误：map.downloadExport不是函数

这是我的代码

example.com

这是我的JS文件

import {Component, ViewEncapsulation} from '@angular/core';
import {MapService} from "../../../shared/leaflet/map.service";
import {GeocodingService} from "../../../shared/leaflet/geocoding.service";


import "leaflet-easybutton";

var leafletImage = require("leaflet-image/leaflet-image")

declare var downloadExport: any;

// import '../../../../leaflet_export.js';

@Component({
  encapsulation: ViewEncapsulation.None,
  selector: 'Home',
  templateUrl: './app/components/tools/sketch/sketch.component.html',
  styleUrls: [ './app/components/tools/sketch/sketch.component.css' ],
  providers: [MapService, GeocodingService]

  })

  export class SketchComponent {

   public vtLayer:any;

   constructor(private mapService: MapService, private geocoder: GeocodingService) {}

   ngOnInit(): void {
console.log('tools component');
   }

   ngAfterViewInit() {

     let map = L.map("map", {
      zoomControl: false,
      center: L.latLng(4.418294, 108.224145),
      zoom: 6,
      minZoom: 4,
      maxZoom:22,
      layers: [this.mapService.baseMaps.OpenStreetMap]
  }).setView([3.1466, 101.6958], 6);


L.control.zoom({ position: "topright" }).addTo(map);
L.control.scale().addTo(map);

var customControl =  L.Control.extend({

  options: {
    position: 'bottomright'
  },

map.addControl(new customControl());

this.mapService.map = map;
    this.geocoder.getCurrentLocation()
        .subscribe(
            location => map.panTo([location.latitude, location.longitude]),
            err => console.error(err)
        );

toolbar
var drawnItems = L.featureGroup();
    map.addLayer(drawnItems);

    var drawControl = new L.Control.Draw(options);
    map.addControl(drawControl);

    map.on(L.Draw.Event.CREATED, function(e:any) {
        var layer = e.layer;

        drawnItems.addLayer(layer);
    });


  function afterRender(result:any) {
    return result;
  }

  function afterExport(result:any) {
    return result;
  }

  function downloadMap(caption:any) {
    var downloadOptions =   {
      caption: {
        text: caption,
        font: '30px Arial',
        fillStyle: 'black',
        position: [100,200]
      },
      exclude: ['.leaflet-control-zoom', '.leaflet-control-attribution'],
      format: 'image/jpeg',
      fileName: 'Map.jpg',
      afterRender: afterRender,
      afterExport: afterExport
  };
    var promise = map.downloadExport(downloadOptions);
    var data = promise.then(function(result:any){
       return result;
    });
    console.log(data)
    }

   }

  }