Avoid keeping adding numbers in headings in Google Docs

I am using a modified version taken from this useful answer to get numbers in my Google Docs Header 2:

function myFunction() {  var pars = DocumentApp.getActiveDocument().getParagraphs();  var counterh2 = 0;  for (var i in pars) {    var par = pars[i];    var hdg = par.getHeading();    if (hdg == DocumentApp.ParagraphHeading.HEADING2) {      counterh2++;      var content = par.getText();      var chunks = content.split('\t');      if (chunks.length > 1) {        par.setText(content.replace(/$[0-9\s]+/, '')); // Not working        par.setText(chunks[1] +''+ counterh2);      } else {        par.setText(content.replace(/$[0-9\s]+/, '')); // Not working        par.setText(chunks[0] +''+ counterh2);      }    }  }}

However, when pressing Run several times, it keeps adding numbers to the Header e.g:

This is the Header 1 1 1

(Pressed Run button 3 times).

I need to edit the Headers several times because I need to add or delete them while I'm writing. It is a dynamic document and not edited only by me.

So how can we prevent adding numbers in Headers in Google Docs?