如何使用jspdf和html2canvas获取生成的pdf文件大小(以字节为单位)

var doc = new jsPDF();
doc.setProperties({
  title: 'Generated PDF',
  author: 'Your Name'
});

html2canvas(document.getElementById('pdf-content')).then(function(canvas) {
  var imgData = canvas.toDataURL('image/png');
  var imgWidth = doc.internal.pageSize.getWidth();
  var imgHeight = (canvas.height * imgWidth) / canvas.width;

  doc.addImage(imgData, 'PNG', 0, 0, imgWidth, imgHeight);
});

var pdfData = doc.output();
var pdfSize = pdfData.length;