code: function unregisterNode (host, node, func) {
    const index = indexOfNode(host, node);
  
    if (index > -1) {
      func(node, 0);
  
      if (canPatchNativeAccessors) {
        nodeToParentNodeMap.set(node, null);
      } else {
        staticProp(node, 'parentNode', null);
      }
  
      arrProto.splice.call(host.childNodes, index, 1);
    }
  }
docs: Cleans up registerNode().