core-js/internals/symbol-constructor-detection.js

'use strict';
/* eslint-disable es/no-symbol -- required for testing */
var V8_VERSION = require('../internals/engine-v8-version');
var fails = require('../internals/fails');
var global = require('../internals/global');

var $String = global.String;

// eslint-disable-next-line es/no-object-getownpropertysymbols -- required for testing
module.exports = !!Object.getOwnPropertySymbols && !fails(function () {
  var symbol = Symbol('symbol detection');
  // Chrome 38 Symbol has incorrect toString conversion
  // `get-own-property-symbols` polyfill symbols converted to object are not Symbol instances
  // nb: Do not call `String` directly to avoid this being optimized out to `symbol+''` which will,
  // of course, fail.
  return !$String(symbol) || !(Object(symbol) instanceof Symbol) ||
    // Chrome 38-40 symbols are not inherited from DOM collections prototypes to instances
    !Symbol.sham && V8_VERSION && V8_VERSION < 41;
});