33 lines
973 B
TypeScript
33 lines
973 B
TypeScript
|
/**
|
||
|
|
* @license
|
||
|
|
* Copyright Google Inc. All Rights Reserved.
|
||
|
|
*
|
||
|
|
* Use of this source code is governed by an MIT-style license that can be
|
||
|
|
* found in the LICENSE file at https://angular.io/license
|
||
|
|
*/
|
||
|
|
|
||
|
|
import {global as _global} from './global';
|
||
|
|
|
||
|
|
// When Symbol.iterator doesn't exist, retrieves the key used in es6-shim
|
||
|
|
declare const Symbol: any;
|
||
|
|
let _symbolIterator: any = null;
|
||
|
|
export function getSymbolIterator(): string|symbol {
|
||
|
|
if (!_symbolIterator) {
|
||
|
|
const Symbol = _global['Symbol'];
|
||
|
|
if (Symbol && Symbol.iterator) {
|
||
|
|
_symbolIterator = Symbol.iterator;
|
||
|
|
} else {
|
||
|
|
// es6-shim specific logic
|
||
|
|
const keys = Object.getOwnPropertyNames(Map.prototype);
|
||
|
|
for (let i = 0; i < keys.length; ++i) {
|
||
|
|
const key = keys[i];
|
||
|
|
if (key !== 'entries' && key !== 'size' &&
|
||
|
|
(Map as any).prototype[key] === Map.prototype['entries']) {
|
||
|
|
_symbolIterator = key;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return _symbolIterator;
|
||
|
|
}
|