ReactNativeComponent.js

/**
 * Copyright 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 ReactNativeComponent
 */

"use strict";

var invariant = require('invariant');
var mergeInto = require('mergeInto');

var genericComponentClass = null;
// This registry keeps track of wrapper classes around native tags
var tagToComponentClass = {};

var ReactNativeComponentInjection = {
  // This accepts a class that receives the tag string. This is a catch all
  // that can render any kind of tag.
  injectGenericComponentClass: function(componentClass) {
    genericComponentClass = componentClass;
  },
  // This accepts a keyed object with classes as values. Each key represents a
  // tag. That particular tag will use this class instead of the generic one.
  injectComponentClasses: function(componentClasses) {
    mergeInto(tagToComponentClass, componentClasses);
  }
};

/**
 * Create an internal class for a specific tag.
 *
 * @param {string} tag The tag for which to create an internal instance.
 * @param {any} props The props passed to the instance constructor.
 * @return {ReactComponent} component The injected empty component.
 */
function createInstanceForTag(tag, props, parentType) {
  var componentClass = tagToComponentClass[tag];
  if (componentClass == null) {
    invariant(
      genericComponentClass,
      'There is no registered component for the tag %s',
      tag
    );
    return new genericComponentClass(tag, props);
  }
  if (parentType === tag) {
    // Avoid recursion
    invariant(
      genericComponentClass,
      'There is no registered component for the tag %s',
      tag
    );
    return new genericComponentClass(tag, props);
  }
  // Unwrap legacy factories
  return new componentClass.type(props);
}

var ReactNativeComponent = {
  createInstanceForTag: createInstanceForTag,
  injection: ReactNativeComponentInjection,
};

module.exports = ReactNativeComponent;