format amount in javascript

function formatToCurrency(amount){
    return (amount).toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,'); 
}
formatToCurrency(12.34546); //"12.35"
formatToCurrency(42345255.356); //"42,345,255.36"const formatToCurrency = amount => {
  return "$" + amount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, "$&,");
};
formatToCurrency(12.34546); //"$12.35"
formatToCurrency(42345255.356); //"$42,345,255.36