How to allow only numbers in textbox in reactjs?

Question

How to allow only numbers in textbox in reactjs using regular expression only?

Answer 1

countDecimals(value) {
  return value % 1 ? value.toString().split(".")[1].length : 0;
};

handleOnChangeAmount(id, e) {
  let count = this.countDecimals(e.target.value);
  if (count === 3) {
    e.preventDefault();
  }
}