JSFiddle - React, Tailwind, and code Playground

HTML

<div class="foo" id="obj">
   I should be changed red
   <div class="bar" style="color:black;">
      I should not be changed red.
      <span class="foo">I should be changed red.</span>
   </div>
</div>

<div class="foo">
   I should not change
   <div class="bar" style="color:black;">
      I should not change
      <span class="foo">I should not change</span>
   </div>
</div>

JavaScript

jQuery.fn.findAndSelf = function (selector){
    return this.find(selector).addBack(selector);
};

$(function(){
    $('#obj').findAndSelf('.foo').css('color', 'red');
});