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59 lines
2.5 KiB
59 lines
2.5 KiB
// `Symbol.prototype.description` getter |
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// https://tc39.es/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 uncurryThis = require('../internals/function-uncurry-this'); |
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var hasOwn = require('../internals/has-own-property'); |
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var isCallable = require('../internals/is-callable'); |
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var isPrototypeOf = require('../internals/object-is-prototype-of'); |
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var toString = require('../internals/to-string'); |
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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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var SymbolPrototype = NativeSymbol && NativeSymbol.prototype; |
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if (DESCRIPTORS && isCallable(NativeSymbol) && (!('description' in SymbolPrototype) || |
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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 : toString(arguments[0]); |
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var result = isPrototypeOf(SymbolPrototype, this) |
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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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SymbolWrapper.prototype = SymbolPrototype; |
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SymbolPrototype.constructor = SymbolWrapper; |
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var NATIVE_SYMBOL = String(NativeSymbol('test')) == 'Symbol(test)'; |
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var symbolToString = uncurryThis(SymbolPrototype.toString); |
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var symbolValueOf = uncurryThis(SymbolPrototype.valueOf); |
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var regexp = /^Symbol\((.*)\)[^)]+$/; |
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var replace = uncurryThis(''.replace); |
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var stringSlice = uncurryThis(''.slice); |
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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 = symbolValueOf(this); |
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var string = symbolToString(symbol); |
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if (hasOwn(EmptyStringDescriptionStore, symbol)) return ''; |
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var desc = NATIVE_SYMBOL ? stringSlice(string, 7, -1) : replace(string, 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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