number string to locale string with commas js code example

Example 1: javascript friendly number format with commas

//ES6 Way
const numberWithCommas = (x) => {
  return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',');
}

Example 2: how to format an integer with a comma in javascript

x.toString().toLocaleString(); // x must be a number