Error in IE when user customfont

[rstuannm]

ERROR: jsPDF PubSub Error Object doesn't support property or method 'toString' TypeError: Object doesn't support property or method 'toString'.

I have my code
const pdf = new jsPDF('l', 'mm', 'a3');
let base64Str = 'AAEAAAANAIAAAwBQRkZUTXas8jIADxLYAAAAHEdERUYAKR.....';
pdf.addFileToVFS('NotoSansCJKjp-Regular.ttf', base64Str);
pdf.addFont('NotoSansCJKjp-Regular.ttf', 'NotoSansCJKjp', 'normal');
pdf.setFont('NotoSansCJKjp');
pdf.setFontSize(12);
pdf.text('取引報告書及び仮想通貨管理明細簿兼残高報告書', 15, 20);
pdf.save('test.pdf');

base64Str i get in https://raw.githubusercontent.com/sphilee/jsPDF-CustomFonts-support/master/dist/default_vfs.js

please help me