// Import annotations from XFDF to FDF
async function main() {
  const fdf_doc = await PDFNet.FDFDoc.createFromXFDF(xfdf_filename);

  // Optionally read XFDF from a string
  const fdf_doc = await PDFNet.FDFDoc.createFromXFDF(xfdf_string);

  // Merge FDF data into PDF doc
  const doc = await PDFNet.PDFDoc.createFromURL(filename);
  await doc.fdfMerge(fdf_doc);
}
PDFNet.runWithCleanup(main);