core-js/internals/symbol-is-registered.js

'use strict';
var getBuiltIn = require('../internals/get-built-in');
var uncurryThis = require('../internals/function-uncurry-this');

var Symbol = getBuiltIn('Symbol');
var keyFor = Symbol.keyFor;
var thisSymbolValue = uncurryThis(Symbol.prototype.valueOf);

// `Symbol.isRegisteredSymbol` method
// https://tc39.es/proposal-symbol-predicates/#sec-symbol-isregisteredsymbol
module.exports = Symbol.isRegisteredSymbol || function isRegisteredSymbol(value) {
  try {
    return keyFor(thisSymbolValue(value)) !== undefined;
  } catch (error) {
    return false;
  }
};