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>}`)
return this._passwordCapability.promise;
    });
    messageHandler.on("DataLoaded", data => {
      
      
      if (loadingTask.onProgress) {
        loadingTask.onProgress({
          loaded: data.length,
          total: data.length,
        });
      }
      this.downloadInfoCapability.resolve(data);
    });
    messageHandler.on("StartRenderPage", data => {
      if (this.destroyed) {
        return; 
      }
      const page = this.pageCache[data.pageIndex];
      page._startRenderPage(data.transparency, data.intent);
    });
    messageHandler.on("commonobj", data => {
      if (this.destroyed) {
        return; 
      }
      const [id, type, exportedData] = data;
      if (this.commonObjs.has(id)) {
        return;
      }
      switch (type) {
        case "Font":