Iterator.zipKeyed implementation

Author: slowcheetah

packages/core-js-compat/src/data.mjs

@@ -2488,6 +2488,8 @@ export const data = {
   },
   'esnext.iterator.zip': {
   },
+  'esnext.iterator.zip-keyed': {
+  },
   'esnext.json.is-raw-json': {
     bun: '1.1.43',
     chrome: '114',

packages/core-js-compat/src/modules-by-versions.mjs

@@ -294,5 +294,6 @@ export default {
     'es.symbol.async-dispose',
     'es.symbol.dispose',
     'esnext.iterator.zip',
+    'esnext.iterator.zip-keyed',
   ],
 };

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

@@ -3,6 +3,7 @@ var parent = require('../../actual/iterator');
 require('../../modules/esnext.iterator.concat');
 require('../../modules/esnext.iterator.range');
 require('../../modules/esnext.iterator.zip');
+require('../../modules/esnext.iterator.zip-keyed');
 // TODO: Remove from `core-js@4`
 require('../../modules/esnext.iterator.as-indexed-pairs');
 require('../../modules/esnext.iterator.indexed');

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

@@ -0,0 +1,10 @@
+'use strict';
+require('../../modules/es.object.to-string');
+require('../../modules/es.object.create');
+require('../../modules/es.iterator.constructor');
+require('../../modules/es.reflect.own-keys');
+require('../../modules/esnext.iterator.zip-keyed');
+
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Iterator', 'zipKeyed');

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

@@ -86,7 +86,7 @@ var IteratorProxy = createIteratorProxy(function () {
     push(results, result);
   }
 
-  return finishResults !== undefined ? finishResults(results) : results;
+  return finishResults ? finishResults(results) : results;
 });
 
 module.exports = function (iters, mode, padding, finishResults) {

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

@@ -0,0 +1,93 @@
+'use strict';
+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 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');
+var uncurryThis = require('../internals/function-uncurry-this');
+
+var create = getBuiltIn('Object', 'create');
+var ownKeys = getBuiltIn('Reflect', 'ownKeys');
+var push = uncurryThis([].push);
+
+// `Iterator.zipKeyed` method
+// https://github.com/tc39/proposal-joint-iteration
+$({ target: 'Iterator', stat: true, forced: true }, {
+  zipKeyed: function zipKeyed(iterables /* , options */) {
+    anObject(iterables);
+    var options = arguments.length > 1 ? arguments[1] : undefined;
+    anObjectOrUndefined(options);
+    var mode = getModeOption(options);
+    var paddingOption = mode === 'longest' ? getPaddingOption(options) : undefined;
+
+    var iters = [];
+    var padding = [];
+    var allKeys = ownKeys(iterables);
+    var keys = [];
+    var desc, i, iter, key, value;
+    for (i = 0; i < allKeys.length; i++) {
+      key = allKeys[i];
+      try {
+        desc = getOwnPropertyDescriptor(iterables, key);
+      } catch (error) {
+        return iteratorCloseAll(iters, 'throw', error);
+      }
+      if (!desc || !desc.enumerable) continue;
+      if (isDataDescriptor(desc)) {
+        value = desc.value;
+      } else {
+        var getter = desc.get;
+        if (getter !== undefined) {
+          try {
+            value = call(getter, iterables);
+          } catch (error) {
+            return iteratorCloseAll(iters, 'throw', error);
+          }
+        }
+      }
+
+      if (value !== undefined) {
+        push(keys, key);
+        try {
+          iter = getIteratorFlattenable(value, true);
+        } catch (error) {
+          return iteratorCloseAll(iters, 'throw', error);
+        }
+        push(iters, iter);
+      }
+    }
+
+    var iterCount = iters.length;
+    if (mode === 'longest') {
+      if (paddingOption === undefined) {
+        for (i = 0; i < iterCount; i++) push(padding, undefined);
+      } else {
+        for (i = 0; i < keys.length; i++) {
+          try {
+            value = paddingOption[keys[i]];
+          } catch (error) {
+            return iteratorCloseAll(iters, 'throw', error);
+          }
+          push(padding, value);
+        }
+      }
+    }
+
+    var finishResults = function (results) {
+      var obj = create(null);
+      for (i = 0; i < iterCount; i++) {
+        obj[keys[i]] = results[i];
+      }
+      return obj;
+    };
+
+    return iteratorZip(iters, mode, padding, finishResults);
+  }
+});

packages/core-js/proposals/joint-iteration.js

@@ -1,3 +1,4 @@
 'use strict';
 // https://github.com/tc39/proposal-joint-iteration
 require('../modules/esnext.iterator.zip');
+require('../modules/esnext.iterator.zip-keyed');

tests/compat/tests.js

@@ -1847,6 +1847,9 @@ GLOBAL.tests = {
   'esnext.iterator.zip': function () {
     return Iterator.zip;
   },
+  'esnext.iterator.zipKeyed': function () {
+    return Iterator.zipKeyed;
+  },
   'esnext.json.is-raw-json': NATIVE_RAW_JSON,
   'esnext.json.parse': function () {
     var unsafeInt = '9007199254740993';

tests/entries/unit.mjs

@@ -773,6 +773,8 @@ for (PATH of ['core-js-pure', 'core-js']) {
     ok(typeof load(NS, 'iterator/indexed') == 'function');
     ok(load(NS, 'iterator/concat')([2]).next().value === 2);
     ok(load(NS, 'iterator/range')(1, 2).next().value === 1);
+    ok(typeof load(NS, 'iterator/zip') == 'function');
+    ok(typeof load(NS, 'iterator/zip-keyed') == 'function');
     ok(load(NS, 'map/delete-all')(new Map(), 1, 2) === false);
     ok(load(NS, 'map/emplace')(new Map([[1, 2]]), 1, { update: it => it ** 2 }) === 4);
     ok(load(NS, 'map/every')(new Map([[1, 2], [2, 3], [3, 4]]), it => it % 2) === false);
@@ -941,6 +943,7 @@ for (PATH of ['core-js-pure', 'core-js']) {
   load('proposals/iterator-helpers-stage-3-2');
   load('proposals/iterator-range');
   load('proposals/iterator-sequencing');
+  load('proposals/joint-iteration');
   load('proposals/json-parse-with-source');
   load('proposals/keys-composition');
   load('proposals/map-update-or-insert');

tests/eslint/eslint.config.js

@@ -1250,6 +1250,7 @@ const forbidCompletelyNonExistentBuiltIns = {
     'concat',
     'range',
     'zip',
+    'zipKeyed',
   ] }],
   'es/no-nonstandard-iterator-prototype-properties': [ERROR, { allow: [
     'toAsync',