51 lines
2.1 KiB
JavaScript
51 lines
2.1 KiB
JavaScript
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// `Symbol.prototype.description` getter
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// https://tc39.github.io/ecma262/#sec-symbol.prototype.description
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'use strict';
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var $ = require('../internals/export');
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var DESCRIPTORS = require('../internals/descriptors');
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var global = require('../internals/global');
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var has = require('../internals/has');
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var isObject = require('../internals/is-object');
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var defineProperty = require('../internals/object-define-property').f;
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var copyConstructorProperties = require('../internals/copy-constructor-properties');
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var NativeSymbol = global.Symbol;
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if (DESCRIPTORS && typeof NativeSymbol == 'function' && (!('description' in NativeSymbol.prototype) ||
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// Safari 12 bug
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NativeSymbol().description !== undefined
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)) {
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var EmptyStringDescriptionStore = {};
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// wrap Symbol constructor for correct work with undefined description
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var SymbolWrapper = function Symbol() {
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var description = arguments.length < 1 || arguments[0] === undefined ? undefined : String(arguments[0]);
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var result = this instanceof SymbolWrapper
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? new NativeSymbol(description)
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// in Edge 13, String(Symbol(undefined)) === 'Symbol(undefined)'
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: description === undefined ? NativeSymbol() : NativeSymbol(description);
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if (description === '') EmptyStringDescriptionStore[result] = true;
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return result;
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};
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copyConstructorProperties(SymbolWrapper, NativeSymbol);
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var symbolPrototype = SymbolWrapper.prototype = NativeSymbol.prototype;
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symbolPrototype.constructor = SymbolWrapper;
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var symbolToString = symbolPrototype.toString;
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var native = String(NativeSymbol('test')) == 'Symbol(test)';
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var regexp = /^Symbol\((.*)\)[^)]+$/;
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defineProperty(symbolPrototype, 'description', {
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configurable: true,
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get: function description() {
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var symbol = isObject(this) ? this.valueOf() : this;
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var string = symbolToString.call(symbol);
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if (has(EmptyStringDescriptionStore, symbol)) return '';
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var desc = native ? string.slice(7, -1) : string.replace(regexp, '$1');
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return desc === '' ? undefined : desc;
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}
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});
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$({ global: true, forced: true }, {
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Symbol: SymbolWrapper
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});
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}
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