Tree Walker

tree-walker.js

function indexTree(root) {
  var treeWalker = document.createTreeWalker(
      root,
      NodeFilter.SHOW_ELEMENT);

  var el;
  while((el = treeWalker.nextNode())) {
      var key = getNodeKey(el);
      if (key) {
          fromNodesLookup[key] = el;
      }
  }
}