com.google.javascript.jscomp.js.util.defineproperty.js Maven / Gradle / Ivy
/*
* Copyright 2016 The Closure Compiler Authors.
*
* 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.
*/
/**
* @fileoverview Provides methods to polyfill native objects.
* @suppress {reportUnknownTypes}
*/
'require util/defines';
/**
* Polyfill for Object.defineProperty() method:
* https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty
*
* Refuses to define properties on Array.prototype and Object.prototype,
* since we can't make them non-enumerable and this messes up peoples' for
* loops. Beyond this, we simply assign values and not worry
* about enumerability or writeability.
*
* @type {(typeof Object.defineProperty)}
* @suppress {reportUnknownTypes}
*/
$jscomp.defineProperty =
$jscomp.ASSUME_ES5 || typeof Object.defineProperties == 'function' ?
Object.defineProperty :
function(target, property, descriptor) {
if (target == Array.prototype ||
// b/155133192
/** @type {?} */ (target) == Object.prototype) {
return target;
}
/**
* NOTE: This is currently never called with a descriptor outside
* the control of the compiler. If we ever decide to polyfill either
* Object.defineProperty or Reflect.defineProperty for ES3, we should
* explicitly check for `get` or `set` on the descriptor and throw a
* TypeError, since it's impossible to properly polyfill it.
*/
target[property] = descriptor.value;
return target;
};