react-addons/lib/shouldUpdateReactComponent.js

Simple packaging of react addons to avoid fiddly 'react/addons' npm module.

/**
 * 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 shouldUpdateReactComponent
 * @typechecks static-only
 */

"use strict";

/**
 * Given a `prevComponent` and `nextComponent`, determines if `prevComponent`
 * should be updated as opposed to being destroyed or replaced.
 *
 * @param {?object} prevComponent
 * @param {?object} nextComponent
 * @return {boolean} True if `prevComponent` should be updated.
 * @protected
 */
function shouldUpdateReactComponent(prevComponent, nextComponent) {
  // TODO: Remove warning after a release.
  if (prevComponent && nextComponent &&
      prevComponent.constructor === nextComponent.constructor && (
        (prevComponent.props && prevComponent.props.key) ===
        (nextComponent.props && nextComponent.props.key)
      )) {
    if (prevComponent._owner === nextComponent._owner) {
      return true;
    } else {
      if ("production" !== process.env.NODE_ENV) {
        if (prevComponent.state) {
          console.warn(
            'A recent change to React has been found to impact your code. ' +
            'A mounted component will now be unmounted and replaced by a ' +
            'component (of the same class) if their owners are different. ' +
            'Previously, ownership was not considered when updating.',
            prevComponent,
            nextComponent
          );
        }
      }
    }
  }
  return false;
}

module.exports = shouldUpdateReactComponent;