React Format Number with Commas Thousand Separators

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <script src="https://unpkg.com/react@17.0.2/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@17.0.2/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/@babel/standalone@7.14.7/babel.min.js"></script>
  </head>

<body>
    <div id="app"></div>
    <script type="text/babel">
      function App() {
        // Method 1: Using Intl.NumberFormat
        const formatNumberIntl = (number) => {
          return new Intl.NumberFormat("it-IT").format(number);
        };

// Method 2: Using a custom function with regex
        const formatNumberCustom = (number) => {
          return number.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ".");
        };

// Method 3: Using toLocaleString with Italian options
        const formatNumberLocale = (number) => {
          return number.toLocaleString("it-IT");
        };

// Method 4: Using parseFloat with fixed decimal places
        const formatNumberFixedDecimals = (number) => {
          return parseFloat(number).toFixed(2).replace(".", ",");
        };

// Method 5: Using a regex to swap decimal and thousands separators
        const formatNumberRegexSwap = (number) => {
          return number
            .toString()
            .replace(/\./g, "X")
            .replace(/,/g, ".")
            .replace(/X/g, ",");
        };

const number = 1234567.89;

return (
          <div className='container'>
            <h3>React js Formatted Number in Italian Style - dot separated (Using different methods):</h3>
            <p>Method 1: {formatNumberIntl(number)}</p>
            <p>Method 2: {formatNumberCustom(number)}</p>
            <p>Method 3: {formatNumberLocale(number)}</p>
            <p>Method 4: {formatNumberFixedDecimals(number)}</p>
            <p>Method 5: {formatNumberRegexSwap(number)}</p>
          </div>
        );
      }

ReactDOM.render(<App />, document.getElementById("app"));
    </script>