JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://rawgithub.com/MikeMcl/bignumber.js/master/bignumber.min.js"></script>
<div id="pi"></div>
<button>step</button>

JavaScript

// using https://rawgithub.com/MikeMcl/bignumber.js/master/bignumber.min.js

$(document).ready(function () {
    
    BigNumber.config({ DECIMAL_PLACES : 50, ERRORS : false});
    
    var pi = new BigNumber(0, 10),
        x = new BigNumber(1, 10),
        two = new BigNumber(2, 10),
        four = new BigNumber(4, 10);

    function iterate() {
        pi = pi.plus(four.dividedBy(x));
        x = x.plus(two);
        pi = pi.minus(four.dividedBy(x));
        x = x.plus(two);
        $("#pi").text(pi.toPrecision(50));
    }

    $('button').click(iterate);
});