JSFiddle - React, Tailwind, and code Playground

HTML

<section id = 'postWrapper'>                          //This is the Second Parent.
  <article id = 'post'>                               //This should be the First Child.
    <section id = 'postInfo'>
      <section id = 'postTitle'></section>
      <section id = 'poster'></section>
      <section id = 'postDate'></section>
    </section>
    <section id = 'postBody'>                       //This should be the Second Child.
    </section>
  </article>
  <section id = 'postBar'>                          //This is the First Parent.
    <img id = 'portrait'>
    <section id = 'editButton'>Edit</section>       //This is the var elem.
    <section id = 'deleteButton'>Delete</section>
  </section>
</section>

JavaScript

var elem = document.getElementById('editButton');
console.log(elem.parentNode.parentNode.childNodes['post'].childNodes['postBody']);    
console.log(elem.parentNode.parentNode.childNodes.childNodes);