JSFiddle - React, Tailwind, and code Playground
HTML
<input id="billable" type='radio' name="teste" value="a">a
JavaScript
$(document).click(function(){
alert( $("#billable:checked").size())
})
<input id="billable" type='radio' name="teste" value="a">a
$(document).click(function(){
alert( $("#billable:checked").size())
})