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