getReactRootElementInContainer.js

/**
 * Copyright 2013-2014 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @providesModule getReactRootElementInContainer
 */

"use strict";

var TEXT_NODE_TYPE = 3;
var COMMENT_NODE_TYPE = 8;
var DOC_NODE_TYPE = 9;

/**
 * @param {DOMNode} node DOM node that may be a text node containing only
 *                       whitespace characters or a comment node.
 *
 * @return {Boolean} true or false whether this node is solely
 *                   comprised of whitespace or a comment.
 */
function isInvisibleNode(node) {
  if (node.nodeType === TEXT_NODE_TYPE) {
    return !(/[^\t\n\r ]/.test(node.data));
  }
  if (node.nodeType === COMMENT_NODE_TYPE) {
    return true;
  }
  return false;
}

/**
 * @param {DOMElement|DOMDocument} container DOM element that may contain
 *                                           a React component.
 * @return {?*} DOM element that may have the reactRoot ID, or null.
 */
function getReactRootElementInContainer(container) {
  if (!container) {
    return null;
  }

  if (container.nodeType === DOC_NODE_TYPE) {
    return container.documentElement;
  } else if (isInvisibleNode(container.firstChild)) {
    // Return the second child in hopes that it is an element node
    return container.childNodes[1];
  } else {
    return container.firstChild;
  }
}

module.exports = getReactRootElementInContainer;