Angular4实现图片上传预览路径不安全的问题解决

<input type="file" (change)="fileChange($event)" >
<img [src]="imgUrl" alt="">

import { Component, OnInit } from '@angular/core';
import { DomSanitizer } from '@angular/platform-browser' 
@Component({
 selector: 'my-app',
 templateUrl: './app.ponent.html',
 styleUrls: ['./app.ponent.css']
})
export class AppComponent implements OnInit { 
 imgUrl;
 constructor(
 private sanitizer: DomSanitizer
 ){} 
 ngOnInit() { } 
 fileChange(event){
 let file = event.target.files[0];
 let imgUrl = window.URL.createObjectURL(file);
 let sanitizerUrl = this.sanitizer.bypassSecurityTrustUrl(imgUrl); 
 this.imgUrl = sanitizerUrl;
 }
}