title: add class to body if any of the pages have a certain class with reactjs
body: <p>How can I add a class to the body if certain page have <code>div</code> has some particular class?</p>
  <p>When switching through the different pages I want to find a certain class and if that class exist I want to add another class to the body.</p>
  <p>How do find a certain class when switching over the pages?</p>