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- // `Symbol.prototype.description` getter
- // https://tc39.es/ecma262/#sec-symbol.prototype.description
- 'use strict';
- var $ = require('../internals/export');
- var DESCRIPTORS = require('../internals/descriptors');
- var global = require('../internals/global');
- var uncurryThis = require('../internals/function-uncurry-this');
- var hasOwn = require('../internals/has-own-property');
- var isCallable = require('../internals/is-callable');
- var isPrototypeOf = require('../internals/object-is-prototype-of');
- var toString = require('../internals/to-string');
- var defineProperty = require('../internals/object-define-property').f;
- var copyConstructorProperties = require('../internals/copy-constructor-properties');
- var NativeSymbol = global.Symbol;
- var SymbolPrototype = NativeSymbol && NativeSymbol.prototype;
- if (DESCRIPTORS && isCallable(NativeSymbol) && (!('description' in SymbolPrototype) ||
- // 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 : toString(arguments[0]);
- var result = isPrototypeOf(SymbolPrototype, this)
- ? 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);
- SymbolWrapper.prototype = SymbolPrototype;
- SymbolPrototype.constructor = SymbolWrapper;
- var NATIVE_SYMBOL = String(NativeSymbol('test')) == 'Symbol(test)';
- var symbolToString = uncurryThis(SymbolPrototype.toString);
- var symbolValueOf = uncurryThis(SymbolPrototype.valueOf);
- var regexp = /^Symbol\((.*)\)[^)]+$/;
- var replace = uncurryThis(''.replace);
- var stringSlice = uncurryThis(''.slice);
- defineProperty(SymbolPrototype, 'description', {
- configurable: true,
- get: function description() {
- var symbol = symbolValueOf(this);
- var string = symbolToString(symbol);
- if (hasOwn(EmptyStringDescriptionStore, symbol)) return '';
- var desc = NATIVE_SYMBOL ? stringSlice(string, 7, -1) : replace(string, regexp, '$1');
- return desc === '' ? undefined : desc;
- }
- });
- $({ global: true, forced: true }, {
- Symbol: SymbolWrapper
- });
- }
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