stylelint-bundle-worker.js
function visit(node, fn) {
  if (!node.visited) {
    define(node, 'visited', true);
    return node.nodes ? mapVisit(node.nodes, fn) : fn(node);
  }
  return node;
}
function visit(node, fn) {
  if (!node.visited) {
    define(node, 'visited', true);
    return node.nodes ? mapVisit(node.nodes, fn) : fn(node);
  }
  return node;
}
Visit `node` with the given `fn`