Refactoring

Author: slowcheetah

CHANGELOG.md

@@ -33,6 +33,10 @@
     - `Error.isError`
   - Moved to stable ES, [May 2025 TC39 meeting](https://github.com/tc39/proposals/commit/a5d4bb99d79f328533d0c36b0cd20597fa12c7a8)
   - Added `es.` namespace module, `/es/` and `/stable/` namespaces entries
+- Added [Joint iteration stage 2.7 proposal](https://github.com/tc39/proposal-joint-iteration):
+  - Built-ins:
+    - `Iterator.zip`
+    - `Iterator.zipKeyed`
 - [`Math.clamp` proposal](https://github.com/tc39/proposal-math-clamp):
   - Built-ins:
     - `Math.clamp`

README.md

@@ -171,6 +171,7 @@ structuredClone(new Set([1, 2, 3])); // => new Set([1, 2, 3])
       - [`Symbol.metadata` for decorators metadata proposal](#symbolmetadata-for-decorators-metadata-proposal)
     - [Stage 2.7 proposals](#stage-27-proposals)
       - [`Iterator` sequencing](#iterator-sequencing)
+      - [Joint iteration](#joint-iteration)
       - [`Map` upsert](#map-upsert)
     - [Stage 2 proposals](#stage-2-proposals)
       - [`AsyncIterator` helpers](#asynciterator-helpers)
@@ -2766,6 +2767,57 @@ Iterator.concat([0, 1].values(), [2, 3], function * () {
 }()).toArray(); // => [0, 1, 2, 3, 4, 5]
 ```
 
+##### [Joint iteration](https://github.com/tc39/proposal-joint-iteration)[⬆](#index)
+Modules [esnext.iterator.zip](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.iterator.zip.js), [esnext.iterator.zip-keyed](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.iterator.zip-keyed.js)
+```ts
+class Iterator {
+  zip<T extends readonly Iterable<unknown>[]>(
+    iterables: T,
+    options?: {
+      mode?: 'shortest' | 'longest' | 'strict';
+      padding?: { [K in keyof T]?: T[K] extends Iterable<infer U> ? U : never };
+    }
+  ): IterableIterator<{ [K in keyof T]: T[K] extends Iterable<infer U> ? U : never }>;
+  zipKeyed<K extends PropertyKey, V extends Record<K, Iterable<unknown>>>(
+    iterables: V,
+    options?: {
+      mode?: 'shortest' | 'longest' | 'strict';
+      padding?: { [P in keyof V]?: V[P] extends Iterable<infer U> ? U : never };
+    }
+  ): IterableIterator<{ [P in keyof V]: V[P] extends Iterable<infer U> ? U : never }>;
+}
+```
+[*CommonJS entry points:*](#commonjs-api)
+```
+core-js/proposals/joint-iteration
+core-js(-pure)/full/iterator/zip
+core-js(-pure)/full/iterator/zip-keyed
+```
+[*Example*](https://tinyurl.com/vutnf2nu):
+```js
+Iterator.zip([
+  [0, 1, 2],
+  [3, 4, 5],
+]).toArray();  // => [[0, 3], [1, 4], [2, 5]]
+
+Iterator.zipKeyed({
+  a: [0, 1, 2],
+  b: [3, 4, 5, 6],
+  c: [7, 8, 9],
+}, {
+  mode: 'longest',
+  padding: { c: 10 },
+}).toArray();
+/*
+[
+  { a: 0,         b: 3, c: 7  },
+  { a: 1,         b: 4, c: 8  },
+  { a: 2,         b: 5, c: 9  },
+  { a: undefined, b: 6, c: 10 },
+];
+ */
+```
+
 ##### [`Map` upsert](https://github.com/thumbsupep/proposal-upsert)[⬆](#index)
 Modules [`esnext.map.get-or-insert`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.map.get-or-insert.js), [`esnext.map.get-or-insert-computed`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.map.get-or-insert-computed.js), [`esnext.weak-map.get-or-insert`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.weak-map.get-or-insert.js) and [`esnext.weak-map.get-or-insert-computed`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.weak-map.get-or-insert-computed.js)
 ```ts

packages/core-js/full/iterator/zip-keyed.js

@@ -1,8 +1,10 @@
 'use strict';
+require('../../modules/es.array.iterator');
 require('../../modules/es.object.to-string');
 require('../../modules/es.object.create');
 require('../../modules/es.iterator.constructor');
 require('../../modules/es.reflect.own-keys');
+require('../../modules/web.dom-collections.iterator');
 require('../../modules/esnext.iterator.zip-keyed');
 
 var entryUnbind = require('../../internals/entry-unbind');

packages/core-js/full/iterator/zip.js

@@ -1,6 +1,8 @@
 'use strict';
+require('../../modules/es.array.iterator');
 require('../../modules/es.object.to-string');
 require('../../modules/es.iterator.constructor');
+require('../../modules/web.dom-collections.iterator');
 require('../../modules/esnext.iterator.zip');
 
 var entryUnbind = require('../../internals/entry-unbind');

packages/core-js/internals/get-iterator-record.js

@@ -0,0 +1,7 @@
+'use strict';
+var getIterator = require('../internals/get-iterator');
+var getIteratorDirect = require('../internals/get-iterator-direct');
+
+module.exports = function (argument) {
+  return getIteratorDirect(getIterator(argument));
+};

packages/core-js/internals/get-padding-option.js

@@ -5,7 +5,7 @@ module.exports = function (iters, kind, value) {
   for (var i = iters.length - 1; i >= 0; i--) {
     if (iters[i] === undefined) continue;
     try {
-      value = iteratorClose(iters[i], kind, value);
+      value = iteratorClose(iters[i].iterator, kind, value);
     } catch (error) {
       kind = 'throw';
       value = error;

packages/core-js/internals/iterator-close-all.js

@@ -9,6 +9,7 @@ var getMethod = require('../internals/get-method');
 var IteratorPrototype = require('../internals/iterators-core').IteratorPrototype;
 var createIterResultObject = require('../internals/create-iter-result-object');
 var iteratorClose = require('../internals/iterator-close');
+var iteratorCloseAll = require('./iterator-close-all');
 
 var TO_STRING_TAG = wellKnownSymbol('toStringTag');
 var ITERATOR_HELPER = 'IteratorHelper';
@@ -47,6 +48,11 @@ var createIteratorProxyPrototype = function (IS_ITERATOR) {
       } catch (error) {
         return iteratorClose(iterator, 'throw', error);
       }
+      if (state.openIters) try {
+        iteratorCloseAll(state.openIters, 'normal');
+      } catch (error) {
+        return iteratorClose(iterator, 'throw', error);
+      }
       if (iterator) iteratorClose(iterator, 'normal');
       return createIterResultObject(undefined, true);
     }

packages/core-js/internals/iterator-create-proxy.js

@@ -39,28 +39,32 @@ var IteratorProxy = createIteratorProxy(function () {
       }
       if (done) {
         openIters[i] = undefined;
+        this.openItersCount--;
         if (mode === 'shortest') {
           this.done = true;
-          return iteratorCloseAll(openIters, 'return', undefined);
+          return iteratorCloseAll(openIters, 'normal', undefined);
         }
         if (mode === 'strict') {
           if (i) {
             this.done = true;
             return iteratorCloseAll(openIters, 'throw', new $TypeError(ITERATOR_IS_EXHAUSTED));
           }
 
-          var open;
+          var open, openDone;
           for (var k = 1; k < iterCount; k++) {
             // eslint-disable-next-line max-depth -- specification case
             try {
               open = call(iters[k].next, iters[k].iterator);
+              openDone = open.done;
+              open = open.value;
             } catch (error) {
               openIters[k] = undefined;
               return iteratorCloseAll(openIters, 'throw', open);
             }
             // eslint-disable-next-line max-depth -- specification case
-            if (!open.value) {
+            if (openDone) {
               openIters[k] = undefined;
+              this.openItersCount--;
             } else {
               this.done = true;
               return iteratorCloseAll(openIters, 'throw', new $TypeError(ITERATOR_IS_EXHAUSTED));
@@ -69,13 +73,7 @@ var IteratorProxy = createIteratorProxy(function () {
           this.done = true;
           return;
         }
-        var isEmptyOpenIters = true;
-        for (var j = 0; j < openIters.length; j++) {
-          if (openIters[j] === undefined) continue;
-          isEmptyOpenIters = false;
-          break;
-        }
-        if (isEmptyOpenIters) {
+        if (!this.openItersCount) {
           this.done = true;
           return;
         }
@@ -91,12 +89,11 @@ var IteratorProxy = createIteratorProxy(function () {
 
 module.exports = function (iters, mode, padding, finishResults) {
   var iterCount = iters.length;
-  var openIters = slice(iters, 0);
-
   return new IteratorProxy({
     iters: iters,
     iterCount: iterCount,
-    openIters: openIters,
+    openIters: slice(iters, 0),
+    openItersCount: iterCount,
     mode: mode,
     padding: padding,
     finishResults: finishResults

packages/core-js/internals/iterator-zip.js

@@ -7,7 +7,6 @@ var getBuiltIn = require('../internals/get-built-in');
 var getOwnPropertyDescriptor = require('../internals/object-get-own-property-descriptor').f;
 var getIteratorFlattenable = require('../internals/get-iterator-flattenable');
 var getModeOption = require('../internals/get-mode-option');
-var getPaddingOption = require('../internals/get-padding-option');
 var isDataDescriptor = require('../internals/is-data-descriptor');
 var iteratorCloseAll = require('../internals/iterator-close-all');
 var iteratorZip = require('../internals/iterator-zip');
@@ -25,7 +24,7 @@ $({ target: 'Iterator', stat: true, forced: true }, {
     var options = arguments.length > 1 ? arguments[1] : undefined;
     anObjectOrUndefined(options);
     var mode = getModeOption(options);
-    var paddingOption = mode === 'longest' ? getPaddingOption(options) : undefined;
+    var paddingOption = mode === 'longest' ? anObjectOrUndefined(options && options.padding) : undefined;
 
     var iters = [];
     var padding = [];
@@ -40,6 +39,7 @@ $({ target: 'Iterator', stat: true, forced: true }, {
         return iteratorCloseAll(iters, 'throw', error);
       }
       if (!desc || !desc.enumerable) continue;
+      value = undefined;
       if (isDataDescriptor(desc)) {
         value = desc.value;
       } else {
@@ -82,8 +82,8 @@ $({ target: 'Iterator', stat: true, forced: true }, {
 
     var finishResults = function (results) {
       var obj = create(null);
-      for (i = 0; i < iterCount; i++) {
-        obj[keys[i]] = results[i];
+      for (var j = 0; j < iterCount; j++) {
+        obj[keys[j]] = results[j];
       }
       return obj;
     };

packages/core-js/modules/esnext.iterator.zip-keyed.js

@@ -3,10 +3,9 @@ var $ = require('../internals/export');
 var anObject = require('../internals/an-object');
 var anObjectOrUndefined = require('../internals/an-object-or-undefined');
 var call = require('../internals/function-call');
-var getIterator = require('../internals/get-iterator');
+var getIteratorRecord = require('../internals/get-iterator-record');
 var getIteratorFlattenable = require('../internals/get-iterator-flattenable');
 var getModeOption = require('../internals/get-mode-option');
-var getPaddingOption = require('../internals/get-padding-option');
 var iteratorClose = require('../internals/iterator-close');
 var iteratorCloseAll = require('../internals/iterator-close-all');
 var iteratorZip = require('../internals/iterator-zip');
@@ -23,52 +22,54 @@ $({ target: 'Iterator', stat: true, forced: true }, {
     var options = arguments.length > 1 ? arguments[1] : undefined;
     anObjectOrUndefined(options);
     var mode = getModeOption(options);
-    var paddingOption = mode === 'longest' ? getPaddingOption(options) : undefined;
+    var paddingOption = mode === 'longest' ? anObjectOrUndefined(options && options.padding) : undefined;
 
     var iters = [];
     var padding = [];
-    var inputIter = getIterator(iterables);
-    var iter, done, result;
+    var inputIter = getIteratorRecord(iterables);
+    var iter, done, next;
     while (!done) {
       try {
-        result = anObject(call(inputIter.next, inputIter));
-        done = result.done;
+        next = anObject(call(inputIter.next, inputIter.iterator));
+        done = next.done;
       } catch (error) {
         return iteratorCloseAll(iters, 'throw', error);
       }
       if (!done) {
         try {
-          iter = getIteratorFlattenable(result.value, true);
+          iter = getIteratorFlattenable(next.value, true);
         } catch (error) {
-          return iteratorCloseAll(concat([inputIter], iters), 'throw', error);
+          return iteratorCloseAll(concat([inputIter.iterator], iters), 'throw', error);
         }
         push(iters, iter);
       }
     }
 
     var iterCount = iters.length;
-    var i, paddingIter;
+    var i, paddingDone, paddingIter;
     if (mode === 'longest') {
       if (paddingOption === undefined) {
         for (i = 0; i < iterCount; i++) push(padding, undefined);
       } else {
         try {
-          paddingIter = getIterator(paddingOption);
+          paddingIter = getIteratorRecord(paddingOption);
         } catch (error) {
           return iteratorCloseAll(iters, 'throw', error);
         }
         var usingIterator = true;
         for (i = 0; i < iterCount; i++) {
           if (usingIterator) {
             try {
-              result = anObject(call(paddingIter.next, paddingIter));
+              next = anObject(call(paddingIter.next, paddingIter.iterator));
+              paddingDone = next.done;
+              next = next.value;
             } catch (error) {
               return iteratorCloseAll(iters, 'throw', error);
             }
-            if (result.done) {
+            if (paddingDone) {
               usingIterator = false;
             } else {
-              push(padding, result.value);
+              push(padding, next);
             }
           } else {
             push(padding, undefined);
@@ -77,7 +78,7 @@ $({ target: 'Iterator', stat: true, forced: true }, {
 
         if (usingIterator) {
           try {
-            iteratorClose(paddingIter, 'normal');
+            iteratorClose(paddingIter.iterator, 'normal');
           } catch (error) {
             return iteratorCloseAll(iters, 'throw', error);
           }

packages/core-js/modules/esnext.iterator.zip.js

@@ -1847,7 +1847,7 @@ GLOBAL.tests = {
   'esnext.iterator.zip': function () {
     return Iterator.zip;
   },
-  'esnext.iterator.zipKeyed': function () {
+  'esnext.iterator.zip-keyed': function () {
     return Iterator.zipKeyed;
   },
   'esnext.json.is-raw-json': NATIVE_RAW_JSON,

tests/compat/tests.js

@@ -1,7 +1,10 @@
-const { from } = Array;
+import { createIterator } from '../helpers/helpers.js';
+import { DESCRIPTORS } from '../helpers/constants.js';
 
 QUnit.test('Iterator.zipKeyed', assert => {
   const { zipKeyed } = Iterator;
+  const { from } = Array;
+  const { defineProperty } = Object;
 
   assert.isFunction(zipKeyed);
   assert.arity(zipKeyed, 1);
@@ -17,4 +20,24 @@ QUnit.test('Iterator.zipKeyed', assert => {
   assert.deepEqual(from(result), [{ a: 0, b: 3, c: 7 }, { a: 1, b: 4, c: 8 }, { a: 2, b: 5, c: 9 }, { a: undefined, b: 6, c: 10 }]);
   result = zipKeyed({ a: [0, 1, 2], b: [3, 4, 5, 6], c: [7, 8, 9] }, { mode: 'strict' });
   assert.throws(() => from(result), TypeError);
+
+  if (DESCRIPTORS) {
+    let obj = {};
+    defineProperty(obj, 'a', { get: () => [0, 1, 2], enumerable: true });
+    defineProperty(obj, 'b', { get: () => [3, 4, 5], enumerable: true });
+    defineProperty(obj, 'c', { get: () => [7, 8, 9], enumerable: true });
+    defineProperty(obj, Symbol('d'), { get: () => [10, 11, 12] });
+    assert.deepEqual(from(zipKeyed(obj)), [{ a: 0, b: 3, c: 7 }, { a: 1, b: 4, c: 8 }, { a: 2, b: 5, c: 9 }]);
+
+    const it = createIterator([1, 2], {
+      return() {
+        this.called = true;
+        return { done: true, value: undefined };
+      },
+    });
+    obj = { a: it };
+    defineProperty(obj, 'b', { get: () => { throw new Error(); }, enumerable: true });
+    assert.throws(() => from(zipKeyed(obj)), Error);
+    assert.true(it.called, 'iterator return called');
+  }
 });