You can use toFixed method for showing 2 decimal point.
let num = 1000;
console.log(num.toFixed(2)); // 1000.00
And you can use Regex like this
function currencyFormat(num) {
return '$' + num.toFixed(2).replace(/(\d)(?=(\d{3})+(?!\d))/g, '$1,')
}
console.log(currencyFormat(2665)); // $2,665.00