在Angular.io项目中加载worker pdf.woker.js的正确方法，

Question

我正在尝试使用Angular.io创建pdf-viewer组件，但我不断收到警告：设置虚假工作程序。在Angular.io中设置工作线程的正确方法是什么？这两个库似乎都已加载，但是pdfjs lib无法启动工作线程。使用最新的角度cli创建项目和组件。最新的pdfjs-dist库。

Angular.json

"assets": [
              "src/favicon.ico",
              "src/assets",
              "src/assets/helloworld.pdf"
            ],
            "styles": [
              "src/styles.css"
            ],
            "scripts": [
              "node_modules/pdfjs-dist/build/pdf.js",
              "node_modules/pdfjs-dist/build/pdf.worker.js"
            ]

pdf-viewer-component.ts

@Component({
  selector: 'app-pdf-viewer',
  templateUrl: './pdf-viewer.component.html',
  styleUrls: ['./pdf-viewer.component.css']
})
export class PdfViewerComponent implements OnInit {

  url = '/assets/helloworld.pdf';
  pdfjsLib = window['pdfjs-dist/build/pdf'];

  constructor() { }

  ngOnInit() {
    this.loadPdf();
  }

  loadPdf() {

    this.pdfjsLib.GlobalWorkerOptions.workerSrc = 'node_modules/pdfjs-dist/build/pdf.worker.js';

    // Asynchronous download of PDF
    const loadingTask = this.pdfjsLib.getDocument(this.url);

    loadingTask.promise.then(function (pdf) {
      console.log('PDF loaded');

      // Fetch the first page
      const pageNumber = 1;
      pdf.getPage(pageNumber).then(function (page) {
        console.log('Page loaded');

        const scale = 1.5;
        const viewport = page.getViewport(scale);

        // Prepare canvas using PDF page dimensions
        const canvas: HTMLCanvasElement = <HTMLCanvasElement>document.getElementById('the-canvas');
        const context = canvas.getContext('2d');
        canvas.height = viewport.height;
        canvas.width = viewport.width;

        // Render PDF page into canvas context
        const renderContext = {
          canvasContext: context,
          viewport: viewport
        };
        const renderTask = page.render(renderContext);
        renderTask.then(function () {
          console.log('Page rendered');
        });
      });
    }, function (reason) {
      // PDF loading error
      console.error(reason);
    });

  }
}