用逗号分隔每3个数字

Question

我想问的第一件事是，是否有更有效的方式编写我的这个程序。第二个问题是为什么在特定数量的字符之后，程序运行不正常并打印零。

function toCurrency(price) {
  var currencyToString = price.toString();
  var finalPrice = "";
  var counterComma = 0;
  for (var i = 0; i < currencyToString.length; i++) {
    counterComma++;
    finalPrice += currencyToString[i];
    if(counterComma == 3){
        counterComma = 0;
      finalPrice += ",";
    }
  }
  return finalPrice;
}

console.log(toCurrency(123456253635423197874));

https://jsfiddle.net/DimitriXd4/68epen4n/