containsNode.js

/**
 * Copyright 2013-2014, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule containsNode
 * @typechecks
 */

var isTextNode = require('isTextNode');

/*jslint bitwise:true */

/**
 * Checks if a given DOM node contains or is another DOM node.
 *
 * @param {?DOMNode} outerNode Outer DOM node.
 * @param {?DOMNode} innerNode Inner DOM node.
 * @return {boolean} True if `outerNode` contains or is `innerNode`.
 */
function containsNode(outerNode, innerNode) {
  if (!outerNode || !innerNode) {
    return false;
  } else if (outerNode === innerNode) {
    return true;
  } else if (isTextNode(outerNode)) {
    return false;
  } else if (isTextNode(innerNode)) {
    return containsNode(outerNode, innerNode.parentNode);
  } else if (outerNode.contains) {
    return outerNode.contains(innerNode);
  } else if (outerNode.compareDocumentPosition) {
    return !!(outerNode.compareDocumentPosition(innerNode) & 16);
  } else {
    return false;
  }
}

module.exports = containsNode;