JSFiddle - React, Tailwind, and code Playground

by salt

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-compat/3.0.0-alpha1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
<div data-bg-check="images">

</div>

<div data-bg-check="images">

</div>
<div data-bg-check="poop">

</div>

JavaScript

var hash = [];
$("[data-bg-check]").each(function (i, div) {
        $.each($(div), function (j, obj) {
        var attr = obj.getAttribute('data-bg-check');
        if (!(attr in hash)) hash[attr] = [];
            hash[attr].push(div);
        });
});
console.log(hash)