jsPDF-AutoTable font size

[phphp]

Sir I have following codes

function generate() {

  var doc = new jsPDF('p', 'pt');
  doc.setFontSize(18);
    doc.text('Chart of Accounts', 220, 50);
    doc.setFontSize(8);
    doc.setTextColor(100);

  var res = doc.autoTableHtmlToJson(document.getElementById("mytable"));
    doc.autoTable(res.columns, res.data, {margin: {top: 70}});
    doc.save("chartofaccounts.pdf");
}

I am trying to set font size 8 to text so I used this line

doc.setFontSize(8);

but it is not working.

Here is link of autotable
[Click Here](Here is link of jsPDF-AutoTable
https://simonbengtsson.github.io/jsPDF-AutoTable/#header-footer)

Please help