how to do separate commas in numbers in js code example

Example 1: number with commas js

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

Example 2: commas for thousands js

var number = 3500;

console.log(new Intl.NumberFormat().format(number));
// → '3,500' if in US English locale