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