react-native/Libraries/vendor/core/copyProperties.js

49 lines
1.3 KiB
JavaScript

/**
* 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 copyProperties
*/
'use strict';
/**
* 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;