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- var $ = require('../internals/export');
- var shared = require('../internals/shared');
- var getBuiltIn = require('../internals/get-built-in');
- var uncurryThis = require('../internals/function-uncurry-this');
- var isSymbol = require('../internals/is-symbol');
- var wellKnownSymbol = require('../internals/well-known-symbol');
- var Symbol = getBuiltIn('Symbol');
- var $isWellKnown = Symbol.isWellKnown;
- var getOwnPropertyNames = getBuiltIn('Object', 'getOwnPropertyNames');
- var thisSymbolValue = uncurryThis(Symbol.prototype.valueOf);
- var WellKnownSymbolsStore = shared('wks');
- for (var i = 0, symbolKeys = getOwnPropertyNames(Symbol), symbolKeysLength = symbolKeys.length; i < symbolKeysLength; i++) {
- // some old engines throws on access to some keys like `arguments` or `caller`
- try {
- var symbolKey = symbolKeys[i];
- if (isSymbol(Symbol[symbolKey])) wellKnownSymbol(symbolKey);
- } catch (error) { /* empty */ }
- }
- // `Symbol.isWellKnown` method
- // https://tc39.es/proposal-symbol-predicates/#sec-symbol-iswellknown
- // We should patch it for newly added well-known symbols. If it's not required, this module just will not be injected
- $({ target: 'Symbol', stat: true, forced: true }, {
- isWellKnown: function isWellKnown(value) {
- if ($isWellKnown && $isWellKnown(value)) return true;
- try {
- var symbol = thisSymbolValue(value);
- for (var j = 0, keys = getOwnPropertyNames(WellKnownSymbolsStore), keysLength = keys.length; j < keysLength; j++) {
- if (WellKnownSymbolsStore[keys[j]] == symbol) return true;
- }
- } catch (error) { /* empty */ }
- return false;
- }
- });
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