copyProperties.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 copyProperties
 */

/**
 * Copy properties from one or more objects (up to 5) into the first object.
 * This is a shallow copy. It mutates the first object and also returns it.
 *
 * NOTE: `arguments` has a very significant performance penalty, which is why
 * we don't support unlimited arguments.
 */
function copyProperties(obj, a, b, c, d, e, f) {
  obj = obj || {};

  if (__DEV__) {
    if (f) {
      throw new Error('Too many arguments passed to copyProperties');
    }
  }

  var args = [a, b, c, d, e];
  var ii = 0, v;
  while (args[ii]) {
    v = args[ii++];
    for (var k in v) {
      obj[k] = v[k];
    }

    // IE ignores toString in object iteration.. See:
    // webreflection.blogspot.com/2007/07/quick-fix-internet-explorer-and.html
    if (v.hasOwnProperty && v.hasOwnProperty('toString') &&
        (typeof v.toString != 'undefined') && (obj.toString !== v.toString)) {
      obj.toString = v.toString;
    }
  }

  return obj;
}

module.exports = copyProperties;

// deprecation notice
console.warn(
  'react/lib/copyProperties has been deprecated and will be removed in the ' +
  'next version of React. All uses can be replaced with ' +
  'Object.assign(obj, a, b, ...) or _.extend(obj, a, b, ...).'
);