function treeWalker(root, func, filter) {
  var treeWalker = document.createTreeWalker(root, filter, null, false);
  let node;

  while (node = treeWalker.nextNode()) {
    func(node);
  }
}
Create a treeWalker
@memberof Core
@param  {element} root element to start with
@param  {function} func function to run on each element
@param  {function | object} filter funtion or object to filter with