1 |
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2 |
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3 | 'use strict';
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4 | var $ = require('../internals/export');
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5 | var DESCRIPTORS = require('../internals/descriptors');
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6 | var global = require('../internals/global');
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7 | var uncurryThis = require('../internals/function-uncurry-this');
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8 | var hasOwn = require('../internals/has-own-property');
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9 | var isCallable = require('../internals/is-callable');
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10 | var isPrototypeOf = require('../internals/object-is-prototype-of');
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11 | var toString = require('../internals/to-string');
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12 | var defineBuiltInAccessor = require('../internals/define-built-in-accessor');
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13 | var copyConstructorProperties = require('../internals/copy-constructor-properties');
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14 |
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15 | var NativeSymbol = global.Symbol;
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16 | var SymbolPrototype = NativeSymbol && NativeSymbol.prototype;
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17 |
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18 | if (DESCRIPTORS && isCallable(NativeSymbol) && (!('description' in SymbolPrototype) ||
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19 |
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20 | NativeSymbol().description !== undefined
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21 | )) {
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22 | var EmptyStringDescriptionStore = {};
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23 |
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24 | var SymbolWrapper = function Symbol() {
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25 | var description = arguments.length < 1 || arguments[0] === undefined ? undefined : toString(arguments[0]);
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26 | var result = isPrototypeOf(SymbolPrototype, this)
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27 | ? new NativeSymbol(description)
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28 |
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29 | : description === undefined ? NativeSymbol() : NativeSymbol(description);
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30 | if (description === '') EmptyStringDescriptionStore[result] = true;
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31 | return result;
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32 | };
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33 |
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34 | copyConstructorProperties(SymbolWrapper, NativeSymbol);
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35 | SymbolWrapper.prototype = SymbolPrototype;
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36 | SymbolPrototype.constructor = SymbolWrapper;
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37 |
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38 | var NATIVE_SYMBOL = String(NativeSymbol('description detection')) === 'Symbol(description detection)';
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39 | var thisSymbolValue = uncurryThis(SymbolPrototype.valueOf);
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40 | var symbolDescriptiveString = uncurryThis(SymbolPrototype.toString);
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41 | var regexp = /^Symbol\((.*)\)[^)]+$/;
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42 | var replace = uncurryThis(''.replace);
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43 | var stringSlice = uncurryThis(''.slice);
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44 |
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45 | defineBuiltInAccessor(SymbolPrototype, 'description', {
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46 | configurable: true,
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47 | get: function description() {
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48 | var symbol = thisSymbolValue(this);
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49 | if (hasOwn(EmptyStringDescriptionStore, symbol)) return '';
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50 | var string = symbolDescriptiveString(symbol);
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51 | var desc = NATIVE_SYMBOL ? stringSlice(string, 7, -1) : replace(string, regexp, '$1');
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52 | return desc === '' ? undefined : desc;
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53 | }
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54 | });
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55 |
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56 | $({ global: true, constructor: true, forced: true }, {
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57 | Symbol: SymbolWrapper
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58 | });
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59 | }
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