JSFiddle - React, Tailwind, and code Playground

HTML

<div class=test data-bar=foo></div>

JavaScript

$.fn.foobar = function() {
    this.each(function() {
        var t = $(this);
        console.log(t);
        
        var foo = t.data("bar");
        console.log(t);
    });
};

$(".test").foobar();