How to store base64 pdf ina variable using html2pdf?

Question

Got a curious situation where if I run google.script.run.savePdf(file, fileName) within .then(), it just doesn't get run when I check the logs in the server-side. If I run it after html2pdf....then(), the file gets saved, but it's empty. So, I thought I'd store it in a variable and pass it to the server side after, but I get an error, as the object returned seems to be illegal.

function savefile() {
  var element = document.getElementById("pgBody");
  var poNumber = document.getElementById('fabricPo').value;
  var supplier = document.getElementById('selectSupplier').value;
  let fileName = supplier + " - " + poNumber + ".pdf";
  var opt = {
    margin: [2, 5, 2, 5], //top, left, bottom, right
    filename: fileName,
    image: {
      type: "jpeg",
      quality: 0.98,
    },
    html2canvas: {
      scale: 2,
    },
    jsPDF: {
      unit: "mm",
      orientation: "landscape",
    },
  };
     let file = ''
 html2pdf()
    .set(opt)
    .from(element)
    .outputPdf()
    .then(function (p) {
      file += btoa(p);
    });
    google.script.run.savePdf(file, fileName);
    window.print();
    google.script.host.close();
} 

Answer 1

Try to use the arrow function.

 html2pdf()
    .set(opt)
    .from(element)
    .outputPdf()
    .then((p) => {
      file += btoa(p);
    });
    google.script.run.savePdf(file, fileName);
    window.print();
    google.script.host.close();

Or use await syntax.

async function savefile() {
  var element = document.getElementById("pgBody");
  var poNumber = document.getElementById('fabricPo').value;
  var supplier = document.getElementById('selectSupplier').value;
  let fileName = supplier + " - " + poNumber + ".pdf";
  var opt = {
    margin: [2, 5, 2, 5], //top, left, bottom, right
    filename: fileName,
    image: {
      type: "jpeg",
      quality: 0.98,
    },
    html2canvas: {
      scale: 2,
    },
    jsPDF: {
      unit: "mm",
      orientation: "landscape",
    },
  };
  let file = ''
  const p = await html2pdf()
    .set(opt)
    .from(element)
    .outputPdf()

    file += btoa(p);
    google.script.run.savePdf(file, fileName);
    window.print();
    google.script.host.close();
}