ui/node_modules/basic-devtools/index.js

/**
 * Given a CSS selector, returns the first matching node, if any.
 * @param {string} css the CSS selector to query
 * @param {Document | DocumentFragment | Element} [root] the optional parent node to query
 * @returns {Element?} the found element, if any
 */
const $ = (css, root = document) => root.querySelector(css);

/**
 * Given a CSS selector, returns a list of all matching nodes.
 * @param {string} css the CSS selector to query
 * @param {Document | DocumentFragment | Element} [root] the optional parent node to query
 * @returns {Element[]} a list of found nodes
 */
const $$ = (css, root = document) => [...root.querySelectorAll(css)];

/**
 * Given a XPath selector, returns a list of all matching nodes.
 * @param {string} path the XPath selector to evaluate
 * @param {Document | DocumentFragment | Element} [root] the optional parent node to query
 * @returns {Node[]} a list of found nodes (elements, attributes, text, comments)
 */
const $x = (path, root = document) => {
  const expression = (new XPathEvaluator).createExpression(path);
  const xpath = expression.evaluate(root, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE);
  const result = [];
  for (let i = 0, {snapshotLength} = xpath; i < snapshotLength; i++)
    result.push(xpath.snapshotItem(i));
  return result;
};

export { $, $$, $x };