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'use strict';
var d = require('d')
, validateSymbol = require('./validate-symbol')
, create = Object.create, defineProperties = Object.defineProperties
, defineProperty = Object.defineProperty, objPrototype = Object.prototype
, Symbol, HiddenSymbol, globalSymbols = create(null);
var generateName = (function () {
var created = create(null);
return function (desc) {
var postfix = 0, name;
while (created[desc + (postfix || '')]) ++postfix;
desc += (postfix || '');
created[desc] = true;
name = '@@' + desc;
defineProperty(objPrototype, name, d.gs(null, function (value) {
defineProperty(this, name, d(value));
}));
return name;
};
}());
HiddenSymbol = function Symbol(description) {
if (this instanceof HiddenSymbol) throw new TypeError('TypeError: Symbol is not a constructor');
return Symbol(description);
};
module.exports = Symbol = function Symbol(description) {
var symbol;
if (this instanceof Symbol) throw new TypeError('TypeError: Symbol is not a constructor');
symbol = create(HiddenSymbol.prototype);
description = (description === undefined ? '' : String(description));
return defineProperties(symbol, {
__description__: d('', description),
__name__: d('', generateName(description))
});
};
defineProperties(Symbol, {
for: d(function (key) {
if (globalSymbols[key]) return globalSymbols[key];
return (globalSymbols[key] = Symbol(String(key)));
}),
keyFor: d(function (s) {
var key;
validateSymbol(s);
for (key in globalSymbols) if (globalSymbols[key] === s) return key;
}),
hasInstance: d('', Symbol('hasInstance')),
isConcatSpreadable: d('', Symbol('isConcatSpreadable')),
iterator: d('', Symbol('iterator')),
match: d('', Symbol('match')),
replace: d('', Symbol('replace')),
search: d('', Symbol('search')),
species: d('', Symbol('species')),
split: d('', Symbol('split')),
toPrimitive: d('', Symbol('toPrimitive')),
toStringTag: d('', Symbol('toStringTag')),
unscopables: d('', Symbol('unscopables'))
});
defineProperties(HiddenSymbol.prototype, {
constructor: d(Symbol),
toString: d('', function () { return this.__name__; })
});
defineProperties(Symbol.prototype, {
toString: d(function () { return 'Symbol (' + validateSymbol(this).__description__ + ')'; }),
valueOf: d(function () { return validateSymbol(this); })
});
defineProperty(Symbol.prototype, Symbol.toPrimitive, d('',
function () { return validateSymbol(this); }));
defineProperty(Symbol.prototype, Symbol.toStringTag, d('c', 'Symbol'));
defineProperty(HiddenSymbol.prototype, Symbol.toPrimitive,
d('c', Symbol.prototype[Symbol.toPrimitive]));
defineProperty(HiddenSymbol.prototype, Symbol.toStringTag,
d('c', Symbol.prototype[Symbol.toStringTag]));
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