https://github.com/mozilla/pdf.js/blob/0df1a5661958df0c4ed2f73b0f3266d825c5c280/src/display/api.js#L710-L719
The return type signature `@returns {Promise<{num: number, gen: number}>}` is mismatched with its definition. (should be `@returns {Promise<number>}`)
if (this.operatorList.lastChunk) {
          this.gfx.endDrawing();
          if (this._canvas) {
            canvasInRendering.delete(this._canvas);
          }
          this.callback();
        }
      }
    }
  }
  return InternalRenderTask;
})();
const version =
  typeof PDFJSDev !== "undefined" ? PDFJSDev.eval("BUNDLE_VERSION") : null;
const build =
  typeof PDFJSDev !== "undefined" ? PDFJSDev.eval("BUNDLE_BUILD") : null;
export {
  build,
  DefaultCanvasFactory,
  DefaultCMapReaderFactory,
  getDocument,
  LoopbackPort,
  PDFDataRangeTransport,
  PDFDocumentProxy,
  PDFPageProxy,
  PDFWorker,
  setPDFNetworkStreamFactory,
  version,
};