Attach (recommended) or Link to PDF file here:  [test.pdf](https://akmer.aikucun.com/a94a8fe5ccb19ba61c4c0873d391e987982fbbd3_1616477914120_83.pdf)


Configuration:
- Web browser and its version: chrome 87.0.4280.88
- Operating system and its version: windows10
- PDF.js version: 2.6.347
- Is a browser extension:

Steps to reproduce the problem:
1. just open 

What is the expected behavior? (add screenshot)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/17724610/112087066-473f8f80-8bc8-11eb-8efb-56139ec42a9c.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

}
            break;
          case "Duplex":
            switch (value.name) {
              case "Simplex":
              case "DuplexFlipShortEdge":
              case "DuplexFlipLongEdge":
                prefValue = value.name;
                break;
              default:
                prefValue = "None";
            }
            break;
          case "PrintPageRange":
            const length = value.length;
            if (length % 2 !== 0) {
              
              break;
            }
            const isValid = value.every((page, i, arr) => {
              return (
                Number.isInteger(page) &&
                page > 0 &&
                (i === 0 || page >= arr[i - 1]) &&
                page <= this.numPages
              );
            });
            if (isValid) {
              prefValue = value;
            }