align handling of optional .next arguments in (Async)Iterator met…

…hods with the current spec draft mainly - ignoring of the first passed to `.next` arguments in built-in generators
zloirock · Aug 28, 2021 · 8df6d0e · 8df6d0e
1 parent 0f1bc28
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## Changelog
 ##### Unreleased
 - `AsyncFromSyncIterator` made stricter, related mainly to `AsyncIterator.from` and `AsyncIterator.prototype.flatMap`
+- Handling of optional `.next` arguments in `(Async)Iterator` methods is aligned with the current spec draft (mainly - ignoring of the first passed to `.next` arguments in built-in generators)
 
 ##### 3.16.3 - 2021.08.25
 - Fixed `CreateAsyncFromSyncIterator` semantic in `AsyncIterator.from`, related to [#765](https://github.com/zloirock/core-js/issues/765)

diff --git a/packages/core-js/internals/async-iterator-create-proxy.js b/packages/core-js/internals/async-iterator-create-proxy.js
@@ -36,16 +36,18 @@ module.exports = function (nextHandler, IS_ITERATOR) {
   var AsyncIteratorProxy = function AsyncIterator(state) {
     state.next = aFunction(state.iterator.next);
     state.done = false;
+    state.ignoreArg = !IS_ITERATOR;
     setInternalState(this, state);
   };
 
   AsyncIteratorProxy.prototype = redefineAll(create(path.AsyncIterator.prototype), {
     next: function next(arg) {
       var state = getInternalState(this);
-      var hasArg = !!arguments.length;
+      var args = arguments.length ? [state.ignoreArg ? undefined : arg] : IS_ITERATOR ? [] : [undefined];
+      state.ignoreArg = false;
       if (state.done) return Promise.resolve({ done: true, value: undefined });
       try {
-        return Promise.resolve(anObject(nextHandler.call(state, Promise, hasArg ? arg : undefined, hasArg)));
+        return Promise.resolve(anObject(nextHandler.call(state, Promise, args)));
       } catch (error) {
         return Promise.reject(error);
       }

diff --git a/packages/core-js/internals/iterator-create-proxy.js b/packages/core-js/internals/iterator-create-proxy.js
@@ -30,13 +30,16 @@ module.exports = function (nextHandler, IS_ITERATOR) {
   var IteratorProxy = function Iterator(state) {
     state.next = aFunction(state.iterator.next);
     state.done = false;
+    state.ignoreArg = !IS_ITERATOR;
     setInternalState(this, state);
   };
 
   IteratorProxy.prototype = redefineAll(create(path.Iterator.prototype), {
-    next: function next() {
+    next: function next(arg) {
       var state = getInternalState(this);
-      var result = state.done ? undefined : nextHandler.apply(state, arguments);
+      var args = arguments.length ? [state.ignoreArg ? undefined : arg] : IS_ITERATOR ? [] : [undefined];
+      state.ignoreArg = false;
+      var result = state.done ? undefined : nextHandler.call(state, args);
       return { done: state.done, value: result };
     },
     'return': $return,

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
@@ -4,11 +4,11 @@ var $ = require('../internals/export');
 var anObject = require('../internals/an-object');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, args) {
   var state = this;
   var iterator = state.iterator;
 
-  return Promise.resolve(anObject(state.next.call(iterator, arg))).then(function (step) {
+  return Promise.resolve(anObject(state.next.apply(iterator, args))).then(function (step) {
     if (anObject(step).done) {
       state.done = true;
       return { done: true, value: undefined };

diff --git a/packages/core-js/modules/esnext.async-iterator.drop.js b/packages/core-js/modules/esnext.async-iterator.drop.js
@@ -5,14 +5,14 @@ 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 (Promise, arg) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, args) {
   var state = this;
 
   return new Promise(function (resolve, reject) {
     var loop = function () {
       try {
         Promise.resolve(
-          anObject(state.next.call(state.iterator, state.remaining ? undefined : arg))
+          anObject(state.next.apply(state.iterator, state.remaining ? [] : args))
         ).then(function (step) {
           try {
             if (anObject(step).done) {

diff --git a/packages/core-js/modules/esnext.async-iterator.filter.js b/packages/core-js/modules/esnext.async-iterator.filter.js
@@ -5,14 +5,14 @@ var aFunction = require('../internals/a-function');
 var anObject = require('../internals/an-object');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, args) {
   var state = this;
   var filterer = state.filterer;
 
   return new Promise(function (resolve, reject) {
     var loop = function () {
       try {
-        Promise.resolve(anObject(state.next.call(state.iterator, arg))).then(function (step) {
+        Promise.resolve(anObject(state.next.apply(state.iterator, args))).then(function (step) {
           try {
             if (anObject(step).done) {
               state.done = true;

diff --git a/packages/core-js/modules/esnext.async-iterator.flat-map.js b/packages/core-js/modules/esnext.async-iterator.flat-map.js
@@ -6,15 +6,15 @@ var anObject = require('../internals/an-object');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 var getAsyncIterator = require('../internals/get-async-iterator');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
   var state = this;
   var mapper = state.mapper;
   var innerIterator;
 
   return new Promise(function (resolve, reject) {
     var outerLoop = function () {
       try {
-        Promise.resolve(anObject(state.next.call(state.iterator, arg))).then(function (step) {
+        Promise.resolve(anObject(state.next.call(state.iterator))).then(function (step) {
           try {
             if (anObject(step).done) {
               state.done = true;

diff --git a/packages/core-js/modules/esnext.async-iterator.from.js b/packages/core-js/modules/esnext.async-iterator.from.js
@@ -15,8 +15,8 @@ var ASYNC_ITERATOR = wellKnownSymbol('asyncIterator');
 
 var AsyncIterator = path.AsyncIterator;
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg, hasArg) {
-  return anObject(this.next.apply(this.iterator, hasArg ? [arg] : []));
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, args) {
+  return anObject(this.next.apply(this.iterator, args));
 }, 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
@@ -5,11 +5,11 @@ var aFunction = require('../internals/a-function');
 var anObject = require('../internals/an-object');
 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
 
-var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, args) {
   var state = this;
   var mapper = state.mapper;
 
-  return Promise.resolve(anObject(state.next.call(state.iterator, arg))).then(function (step) {
+  return Promise.resolve(anObject(state.next.apply(state.iterator, args))).then(function (step) {
     if (anObject(step).done) {
       state.done = true;
       return { done: true, value: undefined };

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 (Promise, arg) {
+var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, args) {
   var iterator = this.iterator;
   var returnMethod, result;
   if (!this.remaining--) {
@@ -18,7 +18,7 @@ var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, arg) {
       });
     }
     return result;
-  } return this.next.call(iterator, arg);
+  } return this.next.apply(iterator, args);
 });
 
 $({ target: 'AsyncIterator', proto: true, real: true }, {

diff --git a/packages/core-js/modules/esnext.iterator.as-indexed-pairs.js b/packages/core-js/modules/esnext.iterator.as-indexed-pairs.js
@@ -4,8 +4,8 @@ var $ = require('../internals/export');
 var anObject = require('../internals/an-object');
 var createIteratorProxy = require('../internals/iterator-create-proxy');
 
-var IteratorProxy = createIteratorProxy(function (arg) {
-  var result = anObject(this.next.call(this.iterator, arg));
+var IteratorProxy = createIteratorProxy(function (args) {
+  var result = anObject(this.next.apply(this.iterator, args));
   var done = this.done = !!result.done;
   if (!done) return [this.index++, result.value];
 });

diff --git a/packages/core-js/modules/esnext.iterator.drop.js b/packages/core-js/modules/esnext.iterator.drop.js
@@ -5,7 +5,7 @@ var anObject = require('../internals/an-object');
 var toPositiveInteger = require('../internals/to-positive-integer');
 var createIteratorProxy = require('../internals/iterator-create-proxy');
 
-var IteratorProxy = createIteratorProxy(function (arg) {
+var IteratorProxy = createIteratorProxy(function (args) {
   var iterator = this.iterator;
   var next = this.next;
   var result, done;
@@ -15,7 +15,7 @@ var IteratorProxy = createIteratorProxy(function (arg) {
     done = this.done = !!result.done;
     if (done) return;
   }
-  result = anObject(next.call(iterator, arg));
+  result = anObject(next.apply(iterator, args));
   done = this.done = !!result.done;
   if (!done) return result.value;
 });

diff --git a/packages/core-js/modules/esnext.iterator.filter.js b/packages/core-js/modules/esnext.iterator.filter.js
@@ -6,13 +6,13 @@ var anObject = require('../internals/an-object');
 var createIteratorProxy = require('../internals/iterator-create-proxy');
 var callWithSafeIterationClosing = require('../internals/call-with-safe-iteration-closing');
 
-var IteratorProxy = createIteratorProxy(function (arg) {
+var IteratorProxy = createIteratorProxy(function (args) {
   var iterator = this.iterator;
   var filterer = this.filterer;
   var next = this.next;
   var result, done, value;
   while (true) {
-    result = anObject(next.call(iterator, arg));
+    result = anObject(next.apply(iterator, args));
     done = this.done = !!result.done;
     if (done) return;
     value = result.value;

diff --git a/packages/core-js/modules/esnext.iterator.flat-map.js b/packages/core-js/modules/esnext.iterator.flat-map.js
@@ -7,7 +7,7 @@ var getIteratorMethod = require('../internals/get-iterator-method');
 var createIteratorProxy = require('../internals/iterator-create-proxy');
 var iteratorClose = require('../internals/iterator-close');
 
-var IteratorProxy = createIteratorProxy(function (arg) {
+var IteratorProxy = createIteratorProxy(function () {
   var iterator = this.iterator;
   var mapper = this.mapper;
   var result, mapped, iteratorMethod, innerIterator;
@@ -20,7 +20,7 @@ var IteratorProxy = createIteratorProxy(function (arg) {
         this.innerIterator = this.innerNext = null;
       }
 
-      result = anObject(this.next.call(iterator, arg));
+      result = anObject(this.next.call(iterator));
 
       if (this.done = !!result.done) return;
 

diff --git a/packages/core-js/modules/esnext.iterator.from.js b/packages/core-js/modules/esnext.iterator.from.js
@@ -9,8 +9,8 @@ var getIteratorMethod = require('../internals/get-iterator-method');
 
 var Iterator = path.Iterator;
 
-var IteratorProxy = createIteratorProxy(function (arg) {
-  var result = anObject(this.next.call(this.iterator, arg));
+var IteratorProxy = createIteratorProxy(function (args) {
+  var result = anObject(this.next.apply(this.iterator, args));
   var done = this.done = !!result.done;
   if (!done) return result.value;
 }, true);

diff --git a/packages/core-js/modules/esnext.iterator.map.js b/packages/core-js/modules/esnext.iterator.map.js
@@ -6,9 +6,9 @@ var anObject = require('../internals/an-object');
 var createIteratorProxy = require('../internals/iterator-create-proxy');
 var callWithSafeIterationClosing = require('../internals/call-with-safe-iteration-closing');
 
-var IteratorProxy = createIteratorProxy(function (arg) {
+var IteratorProxy = createIteratorProxy(function (args) {
   var iterator = this.iterator;
-  var result = anObject(this.next.call(iterator, arg));
+  var result = anObject(this.next.apply(iterator, args));
   var done = this.done = !!result.done;
   if (!done) return callWithSafeIterationClosing(iterator, this.mapper, result.value);
 });

diff --git a/packages/core-js/modules/esnext.iterator.take.js b/packages/core-js/modules/esnext.iterator.take.js
@@ -6,13 +6,13 @@ var toPositiveInteger = require('../internals/to-positive-integer');
 var createIteratorProxy = require('../internals/iterator-create-proxy');
 var iteratorClose = require('../internals/iterator-close');
 
-var IteratorProxy = createIteratorProxy(function (arg) {
+var IteratorProxy = createIteratorProxy(function (args) {
   var iterator = this.iterator;
   if (!this.remaining--) {
     this.done = true;
     return iteratorClose(iterator);
   }
-  var result = anObject(this.next.call(iterator, arg));
+  var result = anObject(this.next.apply(iterator, args));
   var done = this.done = !!result.done;
   if (!done) return result.value;
 });