findClosestMatchingNode

Finds the closest matching node starting at the given node.

• Use a for loop and Node.parentNode to traverse the node tree upwards from the given node.
• Use Element.matches() to check if any given element node matches the provided selector.
• If no matching node is found, return null.

const findClosestMatchingNode = (node, selector) => {
  for (let n = node; n.parentNode; n = n.parentNode)
    if (n.matches && n.matches(selector)) return n;
  return null;
};

findClosestMatchingNode(document.querySelector('span'), 'body'); // body