musix-oss/node_modules/core-js/modules/es.symbol.description.js

// `Symbol.prototype.description` getter
// https://tc39.github.io/ecma262/#sec-symbol.prototype.description
'use strict';
var $ = require('../internals/export');
var DESCRIPTORS = require('../internals/descriptors');
var global = require('../internals/global');
var has = require('../internals/has');
var isObject = require('../internals/is-object');
var defineProperty = require('../internals/object-define-property').f;
var copyConstructorProperties = require('../internals/copy-constructor-properties');

var NativeSymbol = global.Symbol;

if (DESCRIPTORS && typeof NativeSymbol == 'function' && (!('description' in NativeSymbol.prototype) ||
  // Safari 12 bug
  NativeSymbol().description !== undefined
)) {
  var EmptyStringDescriptionStore = {};
  // wrap Symbol constructor for correct work with undefined description
  var SymbolWrapper = function Symbol() {
    var description = arguments.length < 1 || arguments[0] === undefined ? undefined : String(arguments[0]);
    var result = this instanceof SymbolWrapper
      ? new NativeSymbol(description)
      // in Edge 13, String(Symbol(undefined)) === 'Symbol(undefined)'
      : description === undefined ? NativeSymbol() : NativeSymbol(description);
    if (description === '') EmptyStringDescriptionStore[result] = true;
    return result;
  };
  copyConstructorProperties(SymbolWrapper, NativeSymbol);
  var symbolPrototype = SymbolWrapper.prototype = NativeSymbol.prototype;
  symbolPrototype.constructor = SymbolWrapper;

  var symbolToString = symbolPrototype.toString;
  var native = String(NativeSymbol('test')) == 'Symbol(test)';
  var regexp = /^Symbol\((.*)\)[^)]+$/;
  defineProperty(symbolPrototype, 'description', {
    configurable: true,
    get: function description() {
      var symbol = isObject(this) ? this.valueOf() : this;
      var string = symbolToString.call(symbol);
      if (has(EmptyStringDescriptionStore, symbol)) return '';
      var desc = native ? string.slice(7, -1) : string.replace(regexp, '$1');
      return desc === '' ? undefined : desc;
    }
  });

  $({ global: true, forced: true }, {
    Symbol: SymbolWrapper
  });
}