react/src/core/ReactNativeComponent.js

/**
 * Copyright 2014, 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 ReactNativeComponent
 */

'use strict';

var ReactClass = require('ReactClass');
var ReactElement = require('ReactElement');

var assign = require('Object.assign');
var invariant = require('invariant');

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

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 text component class that takes the text string to be
  // rendered as props.
  injectTextComponentClass: function(componentClass) {
    textComponentClass = 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) {
    assign(tagToComponentClass, componentClasses);
  }
};

function autoGenerateWrapperClass(type) {
  return ReactClass.createClass({
    tagName: type.toUpperCase(),
    render: function() {
      return new ReactElement(
        type,
        null,
        null,
        null,
        null,
        this.props
      );
    }
  });
}

/**
 * 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) {
    tagToComponentClass[tag] = componentClass = autoGenerateWrapperClass(tag);
  }
  if (parentType === tag) {
    // Avoid recursion
    invariant(
      genericComponentClass,
      'There is no registered component for the tag %s',
      tag
    );
    return new genericComponentClass(tag, props);
  }
  return new componentClass(props);
}

/**
 * @param {ReactText} text
 * @return {ReactComponent}
 */
function createInstanceForText(text) {
  return new textComponentClass(text);
}

/**
 * @param {ReactComponent} component
 * @return {boolean}
 */
function isTextComponent(component) {
  return component instanceof textComponentClass;
}

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

module.exports = ReactNativeComponent;