es.symbol.js 13 KB

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  1. 'use strict';
  2. var $ = require('../internals/export');
  3. var global = require('../internals/global');
  4. var getBuiltIn = require('../internals/get-built-in');
  5. var IS_PURE = require('../internals/is-pure');
  6. var DESCRIPTORS = require('../internals/descriptors');
  7. var NATIVE_SYMBOL = require('../internals/native-symbol');
  8. var fails = require('../internals/fails');
  9. var has = require('../internals/has');
  10. var isArray = require('../internals/is-array');
  11. var isObject = require('../internals/is-object');
  12. var isSymbol = require('../internals/is-symbol');
  13. var anObject = require('../internals/an-object');
  14. var toObject = require('../internals/to-object');
  15. var toIndexedObject = require('../internals/to-indexed-object');
  16. var toPropertyKey = require('../internals/to-property-key');
  17. var $toString = require('../internals/to-string');
  18. var createPropertyDescriptor = require('../internals/create-property-descriptor');
  19. var nativeObjectCreate = require('../internals/object-create');
  20. var objectKeys = require('../internals/object-keys');
  21. var getOwnPropertyNamesModule = require('../internals/object-get-own-property-names');
  22. var getOwnPropertyNamesExternal = require('../internals/object-get-own-property-names-external');
  23. var getOwnPropertySymbolsModule = require('../internals/object-get-own-property-symbols');
  24. var getOwnPropertyDescriptorModule = require('../internals/object-get-own-property-descriptor');
  25. var definePropertyModule = require('../internals/object-define-property');
  26. var propertyIsEnumerableModule = require('../internals/object-property-is-enumerable');
  27. var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
  28. var redefine = require('../internals/redefine');
  29. var shared = require('../internals/shared');
  30. var sharedKey = require('../internals/shared-key');
  31. var hiddenKeys = require('../internals/hidden-keys');
  32. var uid = require('../internals/uid');
  33. var wellKnownSymbol = require('../internals/well-known-symbol');
  34. var wrappedWellKnownSymbolModule = require('../internals/well-known-symbol-wrapped');
  35. var defineWellKnownSymbol = require('../internals/define-well-known-symbol');
  36. var setToStringTag = require('../internals/set-to-string-tag');
  37. var InternalStateModule = require('../internals/internal-state');
  38. var $forEach = require('../internals/array-iteration').forEach;
  39. var HIDDEN = sharedKey('hidden');
  40. var SYMBOL = 'Symbol';
  41. var PROTOTYPE = 'prototype';
  42. var TO_PRIMITIVE = wellKnownSymbol('toPrimitive');
  43. var setInternalState = InternalStateModule.set;
  44. var getInternalState = InternalStateModule.getterFor(SYMBOL);
  45. var ObjectPrototype = Object[PROTOTYPE];
  46. var $Symbol = global.Symbol;
  47. var $stringify = getBuiltIn('JSON', 'stringify');
  48. var nativeGetOwnPropertyDescriptor = getOwnPropertyDescriptorModule.f;
  49. var nativeDefineProperty = definePropertyModule.f;
  50. var nativeGetOwnPropertyNames = getOwnPropertyNamesExternal.f;
  51. var nativePropertyIsEnumerable = propertyIsEnumerableModule.f;
  52. var AllSymbols = shared('symbols');
  53. var ObjectPrototypeSymbols = shared('op-symbols');
  54. var StringToSymbolRegistry = shared('string-to-symbol-registry');
  55. var SymbolToStringRegistry = shared('symbol-to-string-registry');
  56. var WellKnownSymbolsStore = shared('wks');
  57. var QObject = global.QObject;
  58. // Don't use setters in Qt Script, https://github.com/zloirock/core-js/issues/173
  59. var USE_SETTER = !QObject || !QObject[PROTOTYPE] || !QObject[PROTOTYPE].findChild;
  60. // fallback for old Android, https://code.google.com/p/v8/issues/detail?id=687
  61. var setSymbolDescriptor = DESCRIPTORS && fails(function () {
  62. return nativeObjectCreate(nativeDefineProperty({}, 'a', {
  63. get: function () { return nativeDefineProperty(this, 'a', { value: 7 }).a; }
  64. })).a != 7;
  65. }) ? function (O, P, Attributes) {
  66. var ObjectPrototypeDescriptor = nativeGetOwnPropertyDescriptor(ObjectPrototype, P);
  67. if (ObjectPrototypeDescriptor) delete ObjectPrototype[P];
  68. nativeDefineProperty(O, P, Attributes);
  69. if (ObjectPrototypeDescriptor && O !== ObjectPrototype) {
  70. nativeDefineProperty(ObjectPrototype, P, ObjectPrototypeDescriptor);
  71. }
  72. } : nativeDefineProperty;
  73. var wrap = function (tag, description) {
  74. var symbol = AllSymbols[tag] = nativeObjectCreate($Symbol[PROTOTYPE]);
  75. setInternalState(symbol, {
  76. type: SYMBOL,
  77. tag: tag,
  78. description: description
  79. });
  80. if (!DESCRIPTORS) symbol.description = description;
  81. return symbol;
  82. };
  83. var $defineProperty = function defineProperty(O, P, Attributes) {
  84. if (O === ObjectPrototype) $defineProperty(ObjectPrototypeSymbols, P, Attributes);
  85. anObject(O);
  86. var key = toPropertyKey(P);
  87. anObject(Attributes);
  88. if (has(AllSymbols, key)) {
  89. if (!Attributes.enumerable) {
  90. if (!has(O, HIDDEN)) nativeDefineProperty(O, HIDDEN, createPropertyDescriptor(1, {}));
  91. O[HIDDEN][key] = true;
  92. } else {
  93. if (has(O, HIDDEN) && O[HIDDEN][key]) O[HIDDEN][key] = false;
  94. Attributes = nativeObjectCreate(Attributes, { enumerable: createPropertyDescriptor(0, false) });
  95. } return setSymbolDescriptor(O, key, Attributes);
  96. } return nativeDefineProperty(O, key, Attributes);
  97. };
  98. var $defineProperties = function defineProperties(O, Properties) {
  99. anObject(O);
  100. var properties = toIndexedObject(Properties);
  101. var keys = objectKeys(properties).concat($getOwnPropertySymbols(properties));
  102. $forEach(keys, function (key) {
  103. if (!DESCRIPTORS || $propertyIsEnumerable.call(properties, key)) $defineProperty(O, key, properties[key]);
  104. });
  105. return O;
  106. };
  107. var $create = function create(O, Properties) {
  108. return Properties === undefined ? nativeObjectCreate(O) : $defineProperties(nativeObjectCreate(O), Properties);
  109. };
  110. var $propertyIsEnumerable = function propertyIsEnumerable(V) {
  111. var P = toPropertyKey(V);
  112. var enumerable = nativePropertyIsEnumerable.call(this, P);
  113. if (this === ObjectPrototype && has(AllSymbols, P) && !has(ObjectPrototypeSymbols, P)) return false;
  114. return enumerable || !has(this, P) || !has(AllSymbols, P) || has(this, HIDDEN) && this[HIDDEN][P] ? enumerable : true;
  115. };
  116. var $getOwnPropertyDescriptor = function getOwnPropertyDescriptor(O, P) {
  117. var it = toIndexedObject(O);
  118. var key = toPropertyKey(P);
  119. if (it === ObjectPrototype && has(AllSymbols, key) && !has(ObjectPrototypeSymbols, key)) return;
  120. var descriptor = nativeGetOwnPropertyDescriptor(it, key);
  121. if (descriptor && has(AllSymbols, key) && !(has(it, HIDDEN) && it[HIDDEN][key])) {
  122. descriptor.enumerable = true;
  123. }
  124. return descriptor;
  125. };
  126. var $getOwnPropertyNames = function getOwnPropertyNames(O) {
  127. var names = nativeGetOwnPropertyNames(toIndexedObject(O));
  128. var result = [];
  129. $forEach(names, function (key) {
  130. if (!has(AllSymbols, key) && !has(hiddenKeys, key)) result.push(key);
  131. });
  132. return result;
  133. };
  134. var $getOwnPropertySymbols = function getOwnPropertySymbols(O) {
  135. var IS_OBJECT_PROTOTYPE = O === ObjectPrototype;
  136. var names = nativeGetOwnPropertyNames(IS_OBJECT_PROTOTYPE ? ObjectPrototypeSymbols : toIndexedObject(O));
  137. var result = [];
  138. $forEach(names, function (key) {
  139. if (has(AllSymbols, key) && (!IS_OBJECT_PROTOTYPE || has(ObjectPrototype, key))) {
  140. result.push(AllSymbols[key]);
  141. }
  142. });
  143. return result;
  144. };
  145. // `Symbol` constructor
  146. // https://tc39.es/ecma262/#sec-symbol-constructor
  147. if (!NATIVE_SYMBOL) {
  148. $Symbol = function Symbol() {
  149. if (this instanceof $Symbol) throw TypeError('Symbol is not a constructor');
  150. var description = !arguments.length || arguments[0] === undefined ? undefined : $toString(arguments[0]);
  151. var tag = uid(description);
  152. var setter = function (value) {
  153. if (this === ObjectPrototype) setter.call(ObjectPrototypeSymbols, value);
  154. if (has(this, HIDDEN) && has(this[HIDDEN], tag)) this[HIDDEN][tag] = false;
  155. setSymbolDescriptor(this, tag, createPropertyDescriptor(1, value));
  156. };
  157. if (DESCRIPTORS && USE_SETTER) setSymbolDescriptor(ObjectPrototype, tag, { configurable: true, set: setter });
  158. return wrap(tag, description);
  159. };
  160. redefine($Symbol[PROTOTYPE], 'toString', function toString() {
  161. return getInternalState(this).tag;
  162. });
  163. redefine($Symbol, 'withoutSetter', function (description) {
  164. return wrap(uid(description), description);
  165. });
  166. propertyIsEnumerableModule.f = $propertyIsEnumerable;
  167. definePropertyModule.f = $defineProperty;
  168. getOwnPropertyDescriptorModule.f = $getOwnPropertyDescriptor;
  169. getOwnPropertyNamesModule.f = getOwnPropertyNamesExternal.f = $getOwnPropertyNames;
  170. getOwnPropertySymbolsModule.f = $getOwnPropertySymbols;
  171. wrappedWellKnownSymbolModule.f = function (name) {
  172. return wrap(wellKnownSymbol(name), name);
  173. };
  174. if (DESCRIPTORS) {
  175. // https://github.com/tc39/proposal-Symbol-description
  176. nativeDefineProperty($Symbol[PROTOTYPE], 'description', {
  177. configurable: true,
  178. get: function description() {
  179. return getInternalState(this).description;
  180. }
  181. });
  182. if (!IS_PURE) {
  183. redefine(ObjectPrototype, 'propertyIsEnumerable', $propertyIsEnumerable, { unsafe: true });
  184. }
  185. }
  186. }
  187. $({ global: true, wrap: true, forced: !NATIVE_SYMBOL, sham: !NATIVE_SYMBOL }, {
  188. Symbol: $Symbol
  189. });
  190. $forEach(objectKeys(WellKnownSymbolsStore), function (name) {
  191. defineWellKnownSymbol(name);
  192. });
  193. $({ target: SYMBOL, stat: true, forced: !NATIVE_SYMBOL }, {
  194. // `Symbol.for` method
  195. // https://tc39.es/ecma262/#sec-symbol.for
  196. 'for': function (key) {
  197. var string = $toString(key);
  198. if (has(StringToSymbolRegistry, string)) return StringToSymbolRegistry[string];
  199. var symbol = $Symbol(string);
  200. StringToSymbolRegistry[string] = symbol;
  201. SymbolToStringRegistry[symbol] = string;
  202. return symbol;
  203. },
  204. // `Symbol.keyFor` method
  205. // https://tc39.es/ecma262/#sec-symbol.keyfor
  206. keyFor: function keyFor(sym) {
  207. if (!isSymbol(sym)) throw TypeError(sym + ' is not a symbol');
  208. if (has(SymbolToStringRegistry, sym)) return SymbolToStringRegistry[sym];
  209. },
  210. useSetter: function () { USE_SETTER = true; },
  211. useSimple: function () { USE_SETTER = false; }
  212. });
  213. $({ target: 'Object', stat: true, forced: !NATIVE_SYMBOL, sham: !DESCRIPTORS }, {
  214. // `Object.create` method
  215. // https://tc39.es/ecma262/#sec-object.create
  216. create: $create,
  217. // `Object.defineProperty` method
  218. // https://tc39.es/ecma262/#sec-object.defineproperty
  219. defineProperty: $defineProperty,
  220. // `Object.defineProperties` method
  221. // https://tc39.es/ecma262/#sec-object.defineproperties
  222. defineProperties: $defineProperties,
  223. // `Object.getOwnPropertyDescriptor` method
  224. // https://tc39.es/ecma262/#sec-object.getownpropertydescriptors
  225. getOwnPropertyDescriptor: $getOwnPropertyDescriptor
  226. });
  227. $({ target: 'Object', stat: true, forced: !NATIVE_SYMBOL }, {
  228. // `Object.getOwnPropertyNames` method
  229. // https://tc39.es/ecma262/#sec-object.getownpropertynames
  230. getOwnPropertyNames: $getOwnPropertyNames,
  231. // `Object.getOwnPropertySymbols` method
  232. // https://tc39.es/ecma262/#sec-object.getownpropertysymbols
  233. getOwnPropertySymbols: $getOwnPropertySymbols
  234. });
  235. // Chrome 38 and 39 `Object.getOwnPropertySymbols` fails on primitives
  236. // https://bugs.chromium.org/p/v8/issues/detail?id=3443
  237. $({ target: 'Object', stat: true, forced: fails(function () { getOwnPropertySymbolsModule.f(1); }) }, {
  238. getOwnPropertySymbols: function getOwnPropertySymbols(it) {
  239. return getOwnPropertySymbolsModule.f(toObject(it));
  240. }
  241. });
  242. // `JSON.stringify` method behavior with symbols
  243. // https://tc39.es/ecma262/#sec-json.stringify
  244. if ($stringify) {
  245. var FORCED_JSON_STRINGIFY = !NATIVE_SYMBOL || fails(function () {
  246. var symbol = $Symbol();
  247. // MS Edge converts symbol values to JSON as {}
  248. return $stringify([symbol]) != '[null]'
  249. // WebKit converts symbol values to JSON as null
  250. || $stringify({ a: symbol }) != '{}'
  251. // V8 throws on boxed symbols
  252. || $stringify(Object(symbol)) != '{}';
  253. });
  254. $({ target: 'JSON', stat: true, forced: FORCED_JSON_STRINGIFY }, {
  255. // eslint-disable-next-line no-unused-vars -- required for `.length`
  256. stringify: function stringify(it, replacer, space) {
  257. var args = [it];
  258. var index = 1;
  259. var $replacer;
  260. while (arguments.length > index) args.push(arguments[index++]);
  261. $replacer = replacer;
  262. if (!isObject(replacer) && it === undefined || isSymbol(it)) return; // IE8 returns string on undefined
  263. if (!isArray(replacer)) replacer = function (key, value) {
  264. if (typeof $replacer == 'function') value = $replacer.call(this, key, value);
  265. if (!isSymbol(value)) return value;
  266. };
  267. args[1] = replacer;
  268. return $stringify.apply(null, args);
  269. }
  270. });
  271. }
  272. // `Symbol.prototype[@@toPrimitive]` method
  273. // https://tc39.es/ecma262/#sec-symbol.prototype-@@toprimitive
  274. if (!$Symbol[PROTOTYPE][TO_PRIMITIVE]) {
  275. createNonEnumerableProperty($Symbol[PROTOTYPE], TO_PRIMITIVE, $Symbol[PROTOTYPE].valueOf);
  276. }
  277. // `Symbol.prototype[@@toStringTag]` property
  278. // https://tc39.es/ecma262/#sec-symbol.prototype-@@tostringtag
  279. setToStringTag($Symbol, SYMBOL);
  280. hiddenKeys[HIDDEN] = true;