ReactMarkupChecksum.js

/**
 * Copyright 2013-2014, 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 ReactMarkupChecksum
 */

"use strict";

var adler32 = require('adler32');

var ReactMarkupChecksum = {
  CHECKSUM_ATTR_NAME: 'data-react-checksum',

  /**
   * @param {string} markup Markup string
   * @return {string} Markup string with checksum attribute attached
   */
  addChecksumToMarkup: function(markup) {
    var checksum = adler32(markup);
    return markup.replace(
      '>',
      ' ' + ReactMarkupChecksum.CHECKSUM_ATTR_NAME + '="' + checksum + '">'
    );
  },

  /**
   * @param {string} markup to use
   * @param {DOMElement} element root React element
   * @returns {boolean} whether or not the markup is the same
   */
  canReuseMarkup: function(markup, element) {
    var existingChecksum = element.getAttribute(
      ReactMarkupChecksum.CHECKSUM_ATTR_NAME
    );
    existingChecksum = existingChecksum && parseInt(existingChecksum, 10);
    var markupChecksum = adler32(markup);
    return markupChecksum === existingChecksum;
  }
};

module.exports = ReactMarkupChecksum;