Convert Uint8Array to a file and save to db

Question

I may be asking the basics just now, sorry. I want to convert Uint8Array back to a file and save it in db. Is there anyone who can help me?

document.getElementById('upload_0').onchange = function(event) {
   var ext = $('[name=upload_0]').val().split('.').pop().toLowerCase();
   var file = event.target.files[0];
   var fileReader = new FileReader();
   fileReader.onload = async function() {
      var typedarray = new Uint8Array(this.result);
      const pdfSrcDoc = await PDFLib.PDFDocument.load(typedarray);
      const pdfNewDoc = await PDFLib.PDFDocument.create();
      const pages = await pdfNewDoc.copyPages(pdfSrcDoc, [0,1,2]);
      pages.forEach((page) => pdfNewDoc.addPage(page));
      const newpdf = await pdfNewDoc.save();
      download(newpdf, "sample.pdf", "application/pdf");
   }
   

-> download(newpdf, "sample.pdf", "application/pdf"); I want to convert this part into a file, not download it, and save it in db. Also, I want to save the file name as the original name. Can you tell me what I want to know? Thank you.