pdfDoc.save() returns a corrupted file

[Rahul7S]

Hi community,
I recently started using pdf-lib to alter some exiting pdfs.
Here is what I tried as a POC

function generateModifiedPdf() {
  const formUrl = 'https://pdf-lib.js.org/assets/dod_character.pdf';
  const formPdfBytes = await axios
      .get(formUrl, {
        responseType: 'arraybuffer',
        headers: {
          Accept: 'application/pdf',
        },
      })
      .then((res) => res.data);
  
   const pdfDoc = await PDFDocument.load(formPdfBytes);
   const form = pdfDoc.getForm();

   const nameField = form.getTextField('CharacterName 2');
   nameField.setText('Mario');
      
   return await pdfDoc.save();
}

const modifiedPdf = generateModifiedPdf();

res.contentType('application/pdf').send(modifiedPdf);

But as a result of this what I get is a corrupted pdf file which cannot be opened.

Just to check I tried to return the formPdfBytes from the original file and that works as expected.

Any help here is highly appreciated.

Thank you.

[Rahul7S]

I was able to finally figure out that was wrong here.
I have to return a new Buffer. As below
const modifiedPDF = new Buffer.from(modifiedPDF);