es6.promise.js 9.1 KB

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  1. 'use strict';
  2. var $ = require('./$')
  3. , LIBRARY = require('./$.library')
  4. , global = require('./$.global')
  5. , ctx = require('./$.ctx')
  6. , classof = require('./$.classof')
  7. , $export = require('./$.export')
  8. , isObject = require('./$.is-object')
  9. , anObject = require('./$.an-object')
  10. , aFunction = require('./$.a-function')
  11. , strictNew = require('./$.strict-new')
  12. , forOf = require('./$.for-of')
  13. , setProto = require('./$.set-proto').set
  14. , same = require('./$.same-value')
  15. , SPECIES = require('./$.wks')('species')
  16. , speciesConstructor = require('./$.species-constructor')
  17. , asap = require('./$.microtask')
  18. , PROMISE = 'Promise'
  19. , process = global.process
  20. , isNode = classof(process) == 'process'
  21. , P = global[PROMISE]
  22. , empty = function(){ /* empty */ }
  23. , Wrapper;
  24. var testResolve = function(sub){
  25. var test = new P(empty), promise;
  26. if(sub)test.constructor = function(exec){
  27. exec(empty, empty);
  28. };
  29. (promise = P.resolve(test))['catch'](empty);
  30. return promise === test;
  31. };
  32. var USE_NATIVE = function(){
  33. var works = false;
  34. function P2(x){
  35. var self = new P(x);
  36. setProto(self, P2.prototype);
  37. return self;
  38. }
  39. try {
  40. works = P && P.resolve && testResolve();
  41. setProto(P2, P);
  42. P2.prototype = $.create(P.prototype, {constructor: {value: P2}});
  43. // actual Firefox has broken subclass support, test that
  44. if(!(P2.resolve(5).then(function(){}) instanceof P2)){
  45. works = false;
  46. }
  47. // actual V8 bug, https://code.google.com/p/v8/issues/detail?id=4162
  48. if(works && require('./$.descriptors')){
  49. var thenableThenGotten = false;
  50. P.resolve($.setDesc({}, 'then', {
  51. get: function(){ thenableThenGotten = true; }
  52. }));
  53. works = thenableThenGotten;
  54. }
  55. } catch(e){ works = false; }
  56. return works;
  57. }();
  58. // helpers
  59. var sameConstructor = function(a, b){
  60. // library wrapper special case
  61. if(LIBRARY && a === P && b === Wrapper)return true;
  62. return same(a, b);
  63. };
  64. var getConstructor = function(C){
  65. var S = anObject(C)[SPECIES];
  66. return S != undefined ? S : C;
  67. };
  68. var isThenable = function(it){
  69. var then;
  70. return isObject(it) && typeof (then = it.then) == 'function' ? then : false;
  71. };
  72. var PromiseCapability = function(C){
  73. var resolve, reject;
  74. this.promise = new C(function($$resolve, $$reject){
  75. if(resolve !== undefined || reject !== undefined)throw TypeError('Bad Promise constructor');
  76. resolve = $$resolve;
  77. reject = $$reject;
  78. });
  79. this.resolve = aFunction(resolve),
  80. this.reject = aFunction(reject)
  81. };
  82. var perform = function(exec){
  83. try {
  84. exec();
  85. } catch(e){
  86. return {error: e};
  87. }
  88. };
  89. var notify = function(record, isReject){
  90. if(record.n)return;
  91. record.n = true;
  92. var chain = record.c;
  93. asap(function(){
  94. var value = record.v
  95. , ok = record.s == 1
  96. , i = 0;
  97. var run = function(reaction){
  98. var handler = ok ? reaction.ok : reaction.fail
  99. , resolve = reaction.resolve
  100. , reject = reaction.reject
  101. , result, then;
  102. try {
  103. if(handler){
  104. if(!ok)record.h = true;
  105. result = handler === true ? value : handler(value);
  106. if(result === reaction.promise){
  107. reject(TypeError('Promise-chain cycle'));
  108. } else if(then = isThenable(result)){
  109. then.call(result, resolve, reject);
  110. } else resolve(result);
  111. } else reject(value);
  112. } catch(e){
  113. reject(e);
  114. }
  115. };
  116. while(chain.length > i)run(chain[i++]); // variable length - can't use forEach
  117. chain.length = 0;
  118. record.n = false;
  119. if(isReject)setTimeout(function(){
  120. var promise = record.p
  121. , handler, console;
  122. if(isUnhandled(promise)){
  123. if(isNode){
  124. process.emit('unhandledRejection', value, promise);
  125. } else if(handler = global.onunhandledrejection){
  126. handler({promise: promise, reason: value});
  127. } else if((console = global.console) && console.error){
  128. console.error('Unhandled promise rejection', value);
  129. }
  130. } record.a = undefined;
  131. }, 1);
  132. });
  133. };
  134. var isUnhandled = function(promise){
  135. var record = promise._d
  136. , chain = record.a || record.c
  137. , i = 0
  138. , reaction;
  139. if(record.h)return false;
  140. while(chain.length > i){
  141. reaction = chain[i++];
  142. if(reaction.fail || !isUnhandled(reaction.promise))return false;
  143. } return true;
  144. };
  145. var $reject = function(value){
  146. var record = this;
  147. if(record.d)return;
  148. record.d = true;
  149. record = record.r || record; // unwrap
  150. record.v = value;
  151. record.s = 2;
  152. record.a = record.c.slice();
  153. notify(record, true);
  154. };
  155. var $resolve = function(value){
  156. var record = this
  157. , then;
  158. if(record.d)return;
  159. record.d = true;
  160. record = record.r || record; // unwrap
  161. try {
  162. if(record.p === value)throw TypeError("Promise can't be resolved itself");
  163. if(then = isThenable(value)){
  164. asap(function(){
  165. var wrapper = {r: record, d: false}; // wrap
  166. try {
  167. then.call(value, ctx($resolve, wrapper, 1), ctx($reject, wrapper, 1));
  168. } catch(e){
  169. $reject.call(wrapper, e);
  170. }
  171. });
  172. } else {
  173. record.v = value;
  174. record.s = 1;
  175. notify(record, false);
  176. }
  177. } catch(e){
  178. $reject.call({r: record, d: false}, e); // wrap
  179. }
  180. };
  181. // constructor polyfill
  182. if(!USE_NATIVE){
  183. // 25.4.3.1 Promise(executor)
  184. P = function Promise(executor){
  185. aFunction(executor);
  186. var record = this._d = {
  187. p: strictNew(this, P, PROMISE), // <- promise
  188. c: [], // <- awaiting reactions
  189. a: undefined, // <- checked in isUnhandled reactions
  190. s: 0, // <- state
  191. d: false, // <- done
  192. v: undefined, // <- value
  193. h: false, // <- handled rejection
  194. n: false // <- notify
  195. };
  196. try {
  197. executor(ctx($resolve, record, 1), ctx($reject, record, 1));
  198. } catch(err){
  199. $reject.call(record, err);
  200. }
  201. };
  202. require('./$.redefine-all')(P.prototype, {
  203. // 25.4.5.3 Promise.prototype.then(onFulfilled, onRejected)
  204. then: function then(onFulfilled, onRejected){
  205. var reaction = new PromiseCapability(speciesConstructor(this, P))
  206. , promise = reaction.promise
  207. , record = this._d;
  208. reaction.ok = typeof onFulfilled == 'function' ? onFulfilled : true;
  209. reaction.fail = typeof onRejected == 'function' && onRejected;
  210. record.c.push(reaction);
  211. if(record.a)record.a.push(reaction);
  212. if(record.s)notify(record, false);
  213. return promise;
  214. },
  215. // 25.4.5.1 Promise.prototype.catch(onRejected)
  216. 'catch': function(onRejected){
  217. return this.then(undefined, onRejected);
  218. }
  219. });
  220. }
  221. $export($export.G + $export.W + $export.F * !USE_NATIVE, {Promise: P});
  222. require('./$.set-to-string-tag')(P, PROMISE);
  223. require('./$.set-species')(PROMISE);
  224. Wrapper = require('./$.core')[PROMISE];
  225. // statics
  226. $export($export.S + $export.F * !USE_NATIVE, PROMISE, {
  227. // 25.4.4.5 Promise.reject(r)
  228. reject: function reject(r){
  229. var capability = new PromiseCapability(this)
  230. , $$reject = capability.reject;
  231. $$reject(r);
  232. return capability.promise;
  233. }
  234. });
  235. $export($export.S + $export.F * (!USE_NATIVE || testResolve(true)), PROMISE, {
  236. // 25.4.4.6 Promise.resolve(x)
  237. resolve: function resolve(x){
  238. // instanceof instead of internal slot check because we should fix it without replacement native Promise core
  239. if(x instanceof P && sameConstructor(x.constructor, this))return x;
  240. var capability = new PromiseCapability(this)
  241. , $$resolve = capability.resolve;
  242. $$resolve(x);
  243. return capability.promise;
  244. }
  245. });
  246. $export($export.S + $export.F * !(USE_NATIVE && require('./$.iter-detect')(function(iter){
  247. P.all(iter)['catch'](function(){});
  248. })), PROMISE, {
  249. // 25.4.4.1 Promise.all(iterable)
  250. all: function all(iterable){
  251. var C = getConstructor(this)
  252. , capability = new PromiseCapability(C)
  253. , resolve = capability.resolve
  254. , reject = capability.reject
  255. , values = [];
  256. var abrupt = perform(function(){
  257. forOf(iterable, false, values.push, values);
  258. var remaining = values.length
  259. , results = Array(remaining);
  260. if(remaining)$.each.call(values, function(promise, index){
  261. var alreadyCalled = false;
  262. C.resolve(promise).then(function(value){
  263. if(alreadyCalled)return;
  264. alreadyCalled = true;
  265. results[index] = value;
  266. --remaining || resolve(results);
  267. }, reject);
  268. });
  269. else resolve(results);
  270. });
  271. if(abrupt)reject(abrupt.error);
  272. return capability.promise;
  273. },
  274. // 25.4.4.4 Promise.race(iterable)
  275. race: function race(iterable){
  276. var C = getConstructor(this)
  277. , capability = new PromiseCapability(C)
  278. , reject = capability.reject;
  279. var abrupt = perform(function(){
  280. forOf(iterable, false, function(promise){
  281. C.resolve(promise).then(capability.resolve, reject);
  282. });
  283. });
  284. if(abrupt)reject(abrupt.error);
  285. return capability.promise;
  286. }
  287. });