text: /**
   * 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.
   *
   * @typechecks
   * @providesModule cloneWithProps
   */
  
  "use strict";
  
  var ReactPropTransferer = require('ReactPropTransferer');
  
  var keyOf = require('keyOf');
  var warning = require('warning');
  
  var CHILDREN_PROP = keyOf({children: null});
  
  /**
   * Sometimes you want to change the props of a child passed to you. Usually
   * this is to add a CSS class.
   *
   * @param {object} child child component you'd like to clone
   * @param {object} props props you'd like to modify. They will be merged
   * as if you used `transferPropsTo()`.
   * @return {object} a clone of child with props merged in.
   */
  function cloneWithProps(child, props) {
    if (__DEV__) {
      warning(
        !child.props.ref,
        'You are calling cloneWithProps() on a child with a ref. This is ' +
        'dangerous because you\'re creating a new child which will not be ' +
        'added as a ref to its parent.'
      );
    }
  
    var newProps = ReactPropTransferer.mergeProps(props, child.props);
  
    // Use `child.props.children` if it is provided.
    if (!newProps.hasOwnProperty(CHILDREN_PROP) &&
        child.props.hasOwnProperty(CHILDREN_PROP)) {
      newProps.children = child.props.children;
    }
  
    // The current API doesn't retain _owner and _context, which is why this
    // doesn't use ReactDescriptor.cloneAndReplaceProps.
    return child.constructor(newProps);
  }
  
  module.exports = cloneWithProps;
  