how count decimals javascript

1const num1 = 1.123456789;
2const num2 = 123456789;
3const decimalCount = num => {
4   // Convert to String
5   const numStr = String(num);
6   // String Contains Decimal
7   if (numStr.includes('.')) {
8      return numStr.split('.')[1].length;
9   };
10   // String Does Not Contain Decimal
11   return 0;
12}
13console.log(decimalCount(num1)) // 9
14console.log(decimalCount(num2)) // 0