fix CreateAsyncFromSyncIterator semantic in AsyncIterator.from, r…

…elated to #765
zloirock · Aug 24, 2021 · 0333511 · 0333511
1 parent 4e72728
commit 0333511
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,6 @@
 ## Changelog
 ##### Unreleased
+- Fixed `CreateAsyncFromSyncIterator` semantic in `AsyncIterator.from`, related to [#765](https://github.com/zloirock/core-js/issues/765)
 - Added a workaround of a specific case of broken `Object.prototype`, [#973](https://github.com/zloirock/core-js/issues/973)
 
 ##### 3.16.2 - 2021.08.17

diff --git a/packages/core-js/internals/async-iterator-create-proxy.js b/packages/core-js/internals/async-iterator-create-proxy.js
@@ -42,9 +42,10 @@ module.exports = function (nextHandler, IS_ITERATOR) {
   AsyncIteratorProxy.prototype = redefineAll(create(path.AsyncIterator.prototype), {
     next: function next(arg) {
       var state = getInternalState(this);
+      var hasArg = !!arguments.length;
       if (state.done) return Promise.resolve({ done: true, value: undefined });
       try {
-        return Promise.resolve(anObject(nextHandler.call(state, arg, Promise)));
+        return Promise.resolve(anObject(nextHandler.call(state, Promise, hasArg ? arg : undefined, hasArg)));
       } catch (error) {
         return Promise.reject(error);
       }

diff --git a/packages/core-js/modules/esnext.async-iterator.as-indexed-pairs.js b/packages/core-js/modules/esnext.async-iterator.as-indexed-pairs.js
@@ -4,7 +4,7 @@ var $ = require('../internals/export');
 var anObject = require('../internals/an-object');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
   var state = this;
   var iterator = state.iterator;
 

diff --git a/packages/core-js/modules/esnext.async-iterator.drop.js b/packages/core-js/modules/esnext.async-iterator.drop.js
@@ -5,7 +5,7 @@ var anObject = require('../internals/an-object');
 var toPositiveInteger = require('../internals/to-positive-integer');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
   var state = this;
 
   return new Promise(function (resolve, reject) {

diff --git a/packages/core-js/modules/esnext.async-iterator.filter.js b/packages/core-js/modules/esnext.async-iterator.filter.js
@@ -5,7 +5,7 @@ var aFunction = require('../internals/a-function');
 var anObject = require('../internals/an-object');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
   var state = this;
   var filterer = state.filterer;
 

diff --git a/packages/core-js/modules/esnext.async-iterator.flat-map.js b/packages/core-js/modules/esnext.async-iterator.flat-map.js
@@ -6,7 +6,7 @@ var anObject = require('../internals/an-object');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 var getAsyncIteratorMethod = require('../internals/get-async-iterator-method');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
   var state = this;
   var mapper = state.mapper;
   var innerIterator, iteratorMethod;

diff --git a/packages/core-js/modules/esnext.async-iterator.from.js b/packages/core-js/modules/esnext.async-iterator.from.js
@@ -9,8 +9,12 @@ var getAsyncIteratorMethod = require('../internals/get-async-iterator-method');
 
 var AsyncIterator = path.AsyncIterator;
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg) {
-  return anObject(this.next.call(this.iterator, arg));
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg, hasArg) {
+  var step = anObject(this.next.apply(this.iterator, hasArg ? [arg] : []));
+  var done = step.done;
+  return Promise.resolve(step.value).then(function (value) {
+    return { done: done, value: value };
+  });
 }, true);
 
 $({ target: 'AsyncIterator', stat: true }, {

diff --git a/packages/core-js/modules/esnext.async-iterator.map.js b/packages/core-js/modules/esnext.async-iterator.map.js
@@ -5,7 +5,7 @@ var aFunction = require('../internals/a-function');
 var anObject = require('../internals/an-object');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
   var state = this;
   var mapper = state.mapper;
 

diff --git a/packages/core-js/modules/esnext.async-iterator.take.js b/packages/core-js/modules/esnext.async-iterator.take.js
@@ -5,7 +5,7 @@ var anObject = require('../internals/an-object');
 var toPositiveInteger = require('../internals/to-positive-integer');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
   var iterator = this.iterator;
   var returnMethod, result;
   if (!this.remaining--) {

diff --git a/tests/pure/esnext.async-iterator.from.js b/tests/pure/esnext.async-iterator.from.js
@@ -1,4 +1,5 @@
 import AsyncIterator from 'core-js-pure/features/async-iterator';
+import Promise from 'core-js-pure/features/promise';
 import assign from 'core-js-pure/features/object/assign';
 import values from 'core-js-pure/features/array/values';
 
@@ -14,8 +15,8 @@ QUnit.test('AsyncIterator.from', assert => {
 
   assert.ok(AsyncIterator.from([]) instanceof AsyncIterator, 'proxy, iterable');
 
-  AsyncIterator.from([1, 2, 3]).toArray().then(result => {
-    assert.arrayEqual(result, [1, 2, 3], 'just a proxy');
+  AsyncIterator.from([1, Promise.resolve(2), 3]).toArray().then(result => {
+    assert.arrayEqual(result, [1, 2, 3], 'unwrap promises');
     async();
   });
 

diff --git a/tests/tests/esnext.async-iterator.from.js b/tests/tests/esnext.async-iterator.from.js
@@ -13,8 +13,8 @@ QUnit.test('AsyncIterator.from', assert => {
 
   assert.ok(AsyncIterator.from([]) instanceof AsyncIterator, 'proxy, iterable');
 
-  AsyncIterator.from([1, 2, 3]).toArray().then(result => {
-    assert.arrayEqual(result, [1, 2, 3], 'just a proxy');
+  AsyncIterator.from([1, Promise.resolve(2), 3]).toArray().then(result => {
+    assert.arrayEqual(result, [1, 2, 3], 'unwrap promises');
     async();
   });