how many digits after comma js code example

Example 1: number with commas js

function numberWithCommas(x) {
  return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',');
}

Example 2: format number with commas js

foramtNumber = (num,div=",")=>{
  return num.toString().replace(/\B(?=(\d{3})+(?!\d))/g, div);

}