kitchensink/examples/node_modules/react/lib/findNodeHandle.js

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/**
 * Copyright (c) 2015-present, 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 findNodeHandle
 * 
 */

'use strict';

var _prodInvariant = require('./reactProdInvariant');

var ReactCurrentOwner = require('./ReactCurrentOwner');
var ReactInstanceMap = require('./ReactInstanceMap');

var invariant = require('fbjs/lib/invariant');
var warning = require('fbjs/lib/warning');

/**
 * ReactNative vs ReactWeb
 * -----------------------
 * React treats some pieces of data opaquely. This means that the information
 * is first class (it can be passed around), but cannot be inspected. This
 * allows us to build infrastructure that reasons about resources, without
 * making assumptions about the nature of those resources, and this allows that
 * infra to be shared across multiple platforms, where the resources are very
 * different. General infra (such as `ReactMultiChild`) reasons opaquely about
 * the data, but platform specific code (such as `ReactNativeBaseComponent`) can
 * make assumptions about the data.
 *
 *
 * `rootNodeID`, uniquely identifies a position in the generated native view
 * tree. Many layers of composite components (created with `React.createClass`)
 * can all share the same `rootNodeID`.
 *
 * `nodeHandle`: A sufficiently unambiguous way to refer to a lower level
 * resource (dom node, native view etc). The `rootNodeID` is sufficient for web
 * `nodeHandle`s, because the position in a tree is always enough to uniquely
 * identify a DOM node (we never have nodes in some bank outside of the
 * document). The same would be true for `ReactNative`, but we must maintain a
 * mapping that we can send efficiently serializable
 * strings across native boundaries.
 *
 * Opaque name      TodaysWebReact   FutureWebWorkerReact   ReactNative
 * ----------------------------------------------------------------------------
 * nodeHandle       N/A              rootNodeID             tag
 */

function findNodeHandle(componentOrHandle) {
  if (process.env.NODE_ENV !== 'production') {
    var owner = ReactCurrentOwner.current;
    if (owner !== null) {
      process.env.NODE_ENV !== 'production' ? warning(owner._warnedAboutRefsInRender, '%s is accessing findNodeHandle inside its render(). ' + 'render() should be a pure function of props and state. It should ' + 'never access something that requires stale data from the previous ' + 'render, such as refs. Move this logic to componentDidMount and ' + 'componentDidUpdate instead.', owner.getName() || 'A component') : void 0;
      owner._warnedAboutRefsInRender = true;
    }
  }
  if (componentOrHandle == null) {
    return null;
  }
  if (typeof componentOrHandle === 'number') {
    // Already a node handle
    return componentOrHandle;
  }

  var component = componentOrHandle;

  // TODO (balpert): Wrap iOS native components in a composite wrapper, then
  // ReactInstanceMap.get here will always succeed for mounted components
  var internalInstance = ReactInstanceMap.get(component);
  if (internalInstance) {
    return internalInstance.getHostNode();
  } else {
    var rootNodeID = component._rootNodeID;
    if (rootNodeID) {
      return rootNodeID;
    } else {
      !(
      // Native
      typeof component === 'object' && '_rootNodeID' in component ||
      // Composite
      component.render != null && typeof component.render === 'function') ? process.env.NODE_ENV !== 'production' ? invariant(false, 'findNodeHandle(...): Argument is not a component (type: %s, keys: %s)', typeof component, Object.keys(component)) : _prodInvariant('21', typeof component, Object.keys(component)) : void 0;
      !false ? process.env.NODE_ENV !== 'production' ? invariant(false, 'findNodeHandle(...): Unable to find node handle for unmounted component.') : _prodInvariant('22') : void 0;
    }
  }
}

module.exports = findNodeHandle;