JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<head></head>
<body>
    <a href="something">A</a>
    <a href="something_else">B</a>
    <a href="something">A</a>
    <a href="xxxx">C</a>
</body>
</html>

JavaScript

var counter = 0, cache = {};
$('a').each(function (i, a) {
    a = $(a);
    var href = a.attr('href');
    var c = cache[href];
    if (!c) {
        counter++;
        c = counter;
        cache[href] = c;
    }
    a.text(c + '. ' + a.text());
});