JSFiddle - React, Tailwind, and code Playground

HTML

<div id="xyz" foo="bar">-</div>
<pre id="output"></pre>

JavaScript

var x = "div[foo=bar ]";
var jX = $(x);

$("#output").text(
    ".length          : [" + jX.length + "]\n" +
    ".is(~)           : [" + (jX.is(x) ? "y" : "n") + "]\n" +
    ".filter(~).length: [" + jX.filter(x).length + "]"
); // <<#output>>.text(~)