Check if clicked element is descendant of parent, otherwise remove parent element

Since event.target is a reference to the clicked element, you can check to see if #parent-node is event.target or if it contains event.target as a descendant element.

Example Here

In the snippet below, an event listener is attached to the document. If the element that triggered the click event isn't a descendant of #parent-node and isn't #parent-node, then the element is removed.

document.addEventListener("click", function(e) {
  var element = document.getElementById('parent-node');

  if (e.target !== element && !element.contains(e.target)) {
    element.parentNode.removeChild(element);
  }
});

document.addEventListener("click", function(e) {
  var element = document.getElementById('parent-node');
  
  if (e.target !== element && !element.contains(e.target)) {
    element.parentNode.removeChild(element);
  }
});

#parent-node {
  background-color: #f00;
}

<div id='parent-node'>
  This is the Master Parent node
  <div id='not-parent-node'>
    Not Parent Node
    <button>Button</button>
    <div id='grandchild-node'>
      Grandbaby Node
    </div>
  </div>
</div>

You can use Element.matches() to determine if the Event.target has the id #parent-node or if it is a descendant (#parent-node *).

Then, you can use ChildNode.remove() to delete the parent-node element if the condition is false:

document.addEventListener('click', event => {
  if (!event.target.matches('#parent-node, #parent-node *')) {
    document.getElementById('parent-node').remove();
  }
});