1 | 'use strict';
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2 | var shared = require('../internals/shared');
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3 | var getBuiltIn = require('../internals/get-built-in');
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4 | var uncurryThis = require('../internals/function-uncurry-this');
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5 | var isSymbol = require('../internals/is-symbol');
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6 | var wellKnownSymbol = require('../internals/well-known-symbol');
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7 |
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8 | var Symbol = getBuiltIn('Symbol');
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9 | var $isWellKnownSymbol = Symbol.isWellKnownSymbol;
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10 | var getOwnPropertyNames = getBuiltIn('Object', 'getOwnPropertyNames');
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11 | var thisSymbolValue = uncurryThis(Symbol.prototype.valueOf);
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12 | var WellKnownSymbolsStore = shared('wks');
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13 |
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14 | for (var i = 0, symbolKeys = getOwnPropertyNames(Symbol), symbolKeysLength = symbolKeys.length; i < symbolKeysLength; i++) {
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15 | // some old engines throws on access to some keys like `arguments` or `caller`
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16 | try {
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17 | var symbolKey = symbolKeys[i];
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18 | if (isSymbol(Symbol[symbolKey])) wellKnownSymbol(symbolKey);
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19 | } catch (error) { /* empty */ }
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20 | }
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21 |
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22 | // `Symbol.isWellKnownSymbol` method
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23 | // https://tc39.es/proposal-symbol-predicates/#sec-symbol-iswellknownsymbol
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24 | // We should patch it for newly added well-known symbols. If it's not required, this module just will not be injected
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25 | module.exports = function isWellKnownSymbol(value) {
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26 | if ($isWellKnownSymbol && $isWellKnownSymbol(value)) return true;
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27 | try {
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28 | var symbol = thisSymbolValue(value);
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29 | for (var j = 0, keys = getOwnPropertyNames(WellKnownSymbolsStore), keysLength = keys.length; j < keysLength; j++) {
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30 | // eslint-disable-next-line eqeqeq -- polyfilled symbols case
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31 | if (WellKnownSymbolsStore[keys[j]] == symbol) return true;
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32 | }
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33 | } catch (error) { /* empty */ }
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34 | return false;
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35 | };
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