Angular (8.x)不提供文件上传进度

import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent, HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs';
import { tap } from 'rxjs/operators';

@Injectable()
export class UploadProgressInterceptor implements HttpInterceptor {
  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    if (req.method === 'POST' && req.url.includes('upload')) { // 仅拦截上传请求
      const clonedReq = req.clone({ reportProgress: true }); // 设置报告上传进度
      return next.handle(clonedReq).pipe(
        tap((event: HttpEvent<any>) => {
          if (event instanceof HttpResponse) {
            // 处理上传完成的情况
          } else if (event.type === HttpEventType.UploadProgress) {
            const progress = Math.round((100 * event.loaded) / event.total);
            // 处理上传进度
          }
        })
      );
    }
    return next.handle(req);
  }
}

import { HTTP_INTERCEPTORS } from '@angular/common/http';

providers: [
  {
    provide: HTTP_INTERCEPTORS,
    useClass: UploadProgressInterceptor,
    multi: true
  }
]