JSFiddle - React, Tailwind, and code Playground

JavaScript

function formatNumber(n){
  return Number(n.toFixed(1)).toLocaleString()
}

function formatNumberPeriods(n){
     return formatNumber(n).replace(/,/g,'.');   
}

console.log(formatNumber(82348923489234));
console.log(formatNumberPeriods(82348923489234));